If only I’d had the Ruffwear Beacon years ago, when my old dog Bear went deaf—it would’ve saved me countless hours trying to locate his jet-black body when he’d wander off at night. The lightweight Beacon clips easily on to a collar (or on the Track Jacket; see review) and flashes a high-intensity LED, illuminating your dog in a halo of red light. Multiple blink modes and a watertight seal round out this handy little light’s features. Available at Bob Ward's. $17; ruffwear.com.