Adolph Green

An ISO sleeping bag rating gives a comfort temperature and a lower limit; cold sleepers go by comfort, warm sleepers by the limit, both with a margin.

Smartwatch battery life runs from about a day for a full-screen smartwatch to about two weeks for a fitness-first watch; LTE models connect on their own.

Snowboard bindings are sized to your boot, so pick the binding from the maker's boot chart, then choose straps, a step-on system or a rear-entry design.

Soccer balls run from size 1 to 5 and basketballs from size 3 to 7; the right one depends on the player's age, and basketball size also on the league.

The number on a spinning reel, such as 2500 or 4000, is a size class; higher means a bigger spool, more line and drag and bigger fish, though brands differ.

Swim goggles differ by shape (racing, comfort, open water, mask) and lens (clear, mirrored, tinted, polarized); a good fit gives suction without the strap.

Compare continuous horsepower (CHP), not peak horsepower; walkers need about 2.0 CHP, joggers about 2.5 and regular runners 3.0 or more.

Common water bottles hold 12 to 48 fluid ounces, and a 32 oz bottle is about 946 mL; the right size depends on how often you can refill it during the day.

A 3/2 wetsuit is 3 mm thick at the torso and 2 mm at the arms and legs; O'Neill suggests a 3/2 or 4/3 for water around 55 to 64°F.

Shorter, wider kayaks feel steadier and turn easily, longer, narrower ones track straight and glide faster, and weight capacity must cover you and your gear.

Smartwatch case size is the maker's case measurement in millimeters; we group watches as small (42 mm or less), mid (43 to 46 mm) or large (47 mm+).