Responsive Innovations / Turning Technologies ResponseCard RF RCRF-01 Classroom Clicker.More then one available and they are all in EXCELLENT condition!Battery's may be good or bad. I highly recommend having new ones oh hand anyways because who knows how long the ones that are good will last and some already need replaced. About this Model:Works with all Turning Technologies Classroom RF systems.Dimensions: 3.3" L x 2.1" W x 0.3" H. Weight: 1.0 oz (with batteries).Participants receive answer confirmation on their Response Card through two-way communication.Lightweight, compact, "credit card" format.Successful transmissions are acknowledged on the participant's keypad via a three second long visual green light signal.I package extremely well and ship super fast! - Thanks! B-20