# item.guide
Side-by-Side Comparison Water & Snow

Scuba Tanks vs. Ski & Snowboard Sizing

Comparing 2 standards across 20 specifications. 20 key differences identified.

Comparing:
Scuba Tanks
Ski & Snowboard Sizing

Scuba diving high-pressure cylinders and valves are regulated under ISO 9809 (Steel), ISO 7866 (Aluminum), US DOT-3AL/3AA, and EN 250. The world's most common recreational cylinder is the Aluminum 80 (AL80), with an internal water capacity of 11.1 liters (0.39 cu ft), working pressure of 3,000 psi (207 bar), and delivering 77.4 cu ft (2,192 L) of free air. Cylinder valves connect to first-stage regulators via two distinct standards: Yoke (A-clamp / INT; rated to 232 bar / 3,365 psi) and DIN (G 5/8" threaded connection; rated to 232 bar or 300 bar / 4,350 psi).

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Alpine skis, snowboards, and ski boots are standardized by dimensional geometry, camber/rocker profiles, and the international Mondopoint boot sizing system (ISO 10256 / ISO 9407). All-mountain skis typically span from chin to forehead height (skier height minus 5–15 cm). Snowboard length correlates with rider weight and height (reaching between chest and chin), with waist widths classified from Standard (246–255 mm) to Wide (260+ mm) to prevent boot toe/heel overhang drag. Ski boots are measured strictly in Mondopoint centimeters (foot length in mm).

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Specification Comparison Table

20 Parameters
Parameter / Spec
Aluminum 80 (AL80) Free Air Volume
2,192 liters (77.4 cu ft at rated working pressure)
AL80 Working Pressure
207.0 bar (3,000 psi / 20.7 MPa)
AL80 Internal Water Capacity
11.1 liters (0.39 cu ft internal volume)
AL80 Empty Tare Weight
14.2–14.5 kg (31.4–32.0 lbs without valve)
AL80 Buoyancy (Full vs Empty)
-0.7 kg (-1.6 lbs sink) Full / +1.9 kg (+4.1 lbs float) Empty Seawater Buoyancy
High-Pressure Steel 100 (HP100) Pressure
237.0–300.0 bar (3,442–4,350 psi / 12.9L water capacity)
HP100 Buoyancy (Full vs Empty)
-3.8 kg (-8.4 lbs sink) Full / -1.1 kg (-2.5 lbs sink) Empty Remains negative
Yoke Valve (A-Clamp / INT)
Max 232 bar (3,365 psi; clamp bracket over captured O-ring) Recreational Standard
DIN Valve Standard
G 5/8 in Thread (EN 144-2 / ISO 12209) 232 bar (5 threads) or 300 bar (7 threads)
Hydrostatic Test Cycle
Every 5 Years (at 5/3x working pressure: 5,000 psi for AL80) DOT / ISO Recertification
Alpine Ski Sizing Benchmark
Skier Height minus 5–15 cm (chin-to-forehead height for all-mountain)
Slalom Ski Length Minimum (FIS)
165 (Men) / 155 (Women) cm minimum length for World Cup slalom
Sidecut Turn Radius (R)
11–13 m (Slalom) / 15–20 m (All-Mountain) / 30+ m (GS) Parabolic sidecut radius
Ski Waist Width Tiers
65–75 mm (Carving) / 80–95 mm (All-Mountain) / 100–120 mm (Powder) Underfoot width
Snowboard Sizing Benchmark
Collarbone to Nose Level (Rider weight primary factor) Length in cm
Standard Snowboard Waist Width
246.0–255.0 mm (accommodates US Men's boot sizes 8–10.5)
Mid-Wide Snowboard Waist Width
255.0–260.0 mm (US Men's boot sizes 10.5–11.5)
Wide Snowboard Waist Width
≥ 260.0 mm (US Men's boot sizes 11.5+ to eliminate toe drag)
Ski Boot Sizing System
Mondopoint (ISO 9407) Exact foot length in cm/mm (e.g. 27.5 MP = 275 mm foot)
Boot Sole Length (BSL)
Molded into heel lug in millimeters (e.g., 315 mm BSL for 27.5 MP) Binding fit datum