Garmin Varia RTL515, Cycling Rearview Radar with Tail Light, Visual and Audible Alerts for Vehicles Up to 153 Yards Away - 010-02376-00

Why it's worth it

The Varia RTL515 is a rear light with radar built in. It watches the road behind your rider and warns them about approaching cars, either through a paired bike computer or straight to their phone. It's the rare cycling gift with no size, no fit and almost no compatibility question.

If you don't know much about your rider's setup, buy this one. There's no size to get wrong and no bike it won't fit — it mounts to the seatpost of most road bikes. It works with a Garmin Edge, with the BOLT above, with select Garmin watches, or with nothing but their phone and the free Varia app. That combination of high usefulness and near-zero purchase risk is exactly what you want when you're shopping slightly outside your knowledge.

The specs are simple enough to explain over dinner. Radar picks up vehicles approaching from behind at up to 153 yards, which at normal road speeds gives roughly eight to ten seconds of warning. The tail light is visible from up to a mile in daylight. Wirecutter's cycling safety roundup called radar the single most impactful safety upgrade available to road cyclists, well ahead of ordinary rear lights.

From our review of 8 gifts for cyclists

What we like

• +If you don't know much about your rider's setup, buy this one
• +The specs are simple enough to explain over dinner
• +Here's what makes it land as a gift rather than as equipment
• +Owner feedback also points at something the spec sheet misses: it's unusually good at catching electric cars, which are nearly…

What to know

• –It's a device that needs charging, and it becomes part of the pre-ride routine
• –There's no attachment point for a safety leash, which a few owners have flagged
• –It also can't do much for a rider who mostly stays on bike paths and trails