Watch & Strap Glossary

A working glossary for the watch-curious. Compiled by POPSTRAP, for anyone who reads strap specs the way others read wine labels. Terse definitions, no padding. Bookmark it.

1. Watch Anatomy

Bezel

The ring surrounding the crystal, framing the dial. It can be fixed, rotating, internal, tachymeter, dive-scale, or purely decorative. On the Swatch x Audemars Piguet pocket-watch, the bezel echoes the octagonal Royal Oak signature.

Crown

The knurled knob on the case used to set the time, wind the movement, and adjust the date. On pocket-watches it traditionally sits at 12 o'clock, doubling as the suspension point for a chain or fob.

Case Back

The rear panel of the watch case, either solid (engraved or stamped) or exhibition (sapphire) to reveal the movement. It is the surface where caliber, water resistance, and serial information are typically inscribed.

Lugs

The projecting horns on the case that hold the strap or bracelet via spring bars. Lug width (measured between them in millimeters) determines strap compatibility.

Dial

The visible face of the watch carrying indices, hands, and any complications. Finishes range from sunburst and guilloché to matte enamel and Petite Tapisserie (the AP signature).

Crystal

The transparent cover protecting the dial. Three families dominate: acrylic (warm, scratch-prone, polishable), mineral (mid-tier hardness), and sapphire (Mohs 9, virtually scratchproof, what serious watchmaking demands).

Subdial

A smaller dial set within the main one, used for seconds, chronograph counters, or secondary time zones.

Chapter Ring

The narrow ring on the dial periphery carrying the minute track. Misalignment of the chapter ring is a common factory defect enthusiasts inspect for.

2. Watch Movements

Quartz Movement

An electronic movement regulated by a vibrating quartz crystal at 32,768 Hz. Accurate to within seconds per month, low-cost, and battery-powered — the engine inside most Swatch and Swatch x AP collaborations.

Mechanical Movement

A movement powered by a wound mainspring, with no battery or electronics. Subdivided into manual-wind and automatic.

Automatic Movement

A mechanical movement with a rotor that winds the mainspring through the wearer's motion. Power reserves typically range from 38 to 80 hours.

Escapement

The mechanism that regulates the release of energy from the mainspring to the balance wheel. The Swiss lever escapement dominates.

Complication

Any function beyond hours, minutes, and seconds. Includes date, chronograph, GMT, moonphase, perpetual calendar, minute repeater, and tourbillon — in roughly ascending order of complexity and price.

Tourbillon

A rotating cage holding the escapement and balance, designed to average out positional errors caused by gravity. Largely a showcase of craftsmanship in modern wristwatches.

Power Reserve

The duration a fully wound movement will run before stopping.

3. Strap Types & Materials

NATO Strap

A single-pass nylon strap with a backing layer under the case, originally G10 military issue. Cheap, durable, and infinitely swappable.

Leather Strap

Traditional dress and casual choice. Variants include calfskin, alligator, shell cordovan, suede, and vintage-style oiled leather. Hates water.

Silicone Strap

A flexible synthetic strap made from cured silicone elastomer. Hypoallergenic, water-resistant, dust-shedding, and resistant to UV and temperature swings. The material we know best.

FKM Rubber (Fluoroelastomer)

A high-performance synthetic rubber resistant to oils, chemicals, and extreme temperatures. Denser and more chemically inert than silicone.

Vulcanized Rubber

Natural or synthetic rubber cross-linked via sulfur and heat to become elastic and durable. The classic dive-strap material before silicone and FKM took over.

Cage Strap

A strap that wraps and encloses the watch case in a structural sleeve, securing it without using factory lugs or spring bars. The format POPSTRAP builds for the Swatch x Audemars Piguet 40mm pocket-watch.

Tropic Strap

A perforated rubber strap pattern originating in the 1960s for divers. The waffle texture allows water drainage and air circulation.

Mesh Bracelet

A woven metal bracelet, also called Milanese. Comfortable, breathable, and infinitely adjustable on sliding clasps.

4. Strap Anatomy

Spring Bar

The sprung steel pin that holds a strap or bracelet into the watch lugs. Standard diameters are 1.5mm and 1.8mm.

Buckle

The closing hardware of a strap. Comes in tang (pin), deployant (folding), butterfly (double-folding), and bracelet-style varieties.

Tang Buckle

The classic pin-and-frame closure used on most straps. The tang (pin) passes through a hole in the strap to secure it.

Deployant Clasp

A folding metal clasp that keeps the strap permanently looped, opening only at the clasp. Preserves leather and improves security at the cost of bulk.

Keeper

The loop (fixed or floating) that secures the free end of the strap after the buckle. Most straps have one fixed and one floating keeper.

Quick-Release

A spring bar with a small lever, allowing strap changes without tools. Common on contemporary watches.

Lug Width

The distance between the lugs, defining strap compatibility. The Swatch x AP 40mm pocket-watch takes 24mm straps.

5. Technical Specs

Shore A Hardness

A scale measuring the hardness of soft elastomers like silicone and rubber. Watch straps typically fall between 50A (very soft, marshmallow-flex) and 70A (firm, structured). POPSTRAP cage straps are engineered around the upper range for case retention.

ISO 22810

The international standard governing water resistance of watches not classified as divers.

ATM

Atmospheres — a unit of pressure where 1 ATM equals roughly 10 meters of static water depth. A 5 ATM watch is splash- and shower-safe; 10 ATM tolerates swimming; 20 ATM is for diving.

ppm (parts per million)

A measure of trace concentration, used to certify the absence of harmful substances (lead, phthalates, BPA) in food- and skin-contact materials.

Hypoallergenic

Describes a material unlikely to provoke an allergic reaction. For straps, this means the absence of nickel, latex proteins, and reactive plasticizers — silicone is inherently hypoallergenic when properly cured.

Biocompatibility (ISO 10993)

The international standard testing materials for skin contact and medical use. Medical-grade silicone is tested under this protocol.

6. Watch Industry Slang

NOS

New Old Stock. A watch (or part) that is unsold, unused, original-condition inventory from a previous era.

BNIB

Brand New In Box. A watch in original packaging, with warranty and tags intact.

Daily Beater

The watch you actually wear without fear — durable, replaceable, and emotionally low-stakes.

GADA

Go Anywhere, Do Anything. A versatile single-watch solution — typically a sporty automatic with a date, on a bracelet, around 36-40mm.

Holy Trinity

The three traditional pinnacles of haute horlogerie: Patek Philippe, Audemars Piguet, and Vacheron Constantin.

Grail

The watch a collector aspires to but does not yet own. Highly personal, often financially absurd.

Patina

The aging of dial, hands, lume, or case finish over decades. Celebrated when honest, faked when not.

Microbrand

An independent, small-batch watch brand operating outside the major Swiss groups. Often crowdfunded, design-led, and direct-to-consumer.

7. Materials Science

Medical-Grade Silicone

A platinum-cured silicone formulation tested for biocompatibility (ISO 10993) and free of fillers, plasticizers, and reactive byproducts. Safe for prolonged skin contact, sterilizable, and stable across wide temperature ranges.

Platinum-Cured Silicone

Silicone cross-linked via a platinum catalyst, yielding cleaner, odorless, more biocompatible material than peroxide-cured alternatives.

Polymer / Elastomer

A polymer is a large molecule built from repeating subunits. An elastomer is a polymer with elastic properties — it deforms under stress and returns to shape. Silicone and FKM are both elastomers.

Plasticizer

An additive used to soften plastics and rubbers. Some plasticizers (phthalates, BPA) are skin-irritants — properly formulated medical silicone uses none.

Vulcanization

The cross-linking process for natural and synthetic rubber, using sulfur and heat. Invented by Charles Goodyear in 1839.

8. Manufacturing

Injection Molding

The process of injecting molten or liquid material into a closed mold under pressure. For silicone straps, LSR (liquid silicone rubber) injection molding is the precision standard.

LSR (Liquid Silicone Rubber)

A two-part silicone system mixed and injected at high pressure into heated molds. Produces tight tolerances, clean edges, and consistent material properties batch to batch.

CNC Machining

Computer Numerical Control — the subtractive machining of metal or polymer parts from solid stock. Used in cases, buckles, and high-precision strap hardware.

In-House Movement

A movement designed, developed, and manufactured by the watch brand itself, rather than sourced from ETA, Sellita, or Miyota.

Hand-Finishing

The manual decoration of movement components — anglage (beveling), Côtes de Genève, perlage, black polishing. The visible signature of haute horlogerie.

Mold Tooling

The precision-machined steel cavity used in injection molding. A serious tool costs thousands and lasts hundreds of thousands of cycles — the upfront commitment behind any small-batch silicone product.

Quality Control (QC)

The dimensional, visual, and material inspection of finished parts before they leave the factory. Tolerances on a cage strap are tighter than on a flat strap — every millimeter affects case retention.

Further reading from POPSTRAP:

Worn quiet. Built loud.