Amazon.com : Zorpia Pack of 5 Color Hand Held Tally Counter 4 Digit Mechanical Palm Clicker Counter - Assorted Color Handheld Tally Counter for Lap/Sport/Coach/School/Event (Pack of 5) : Sports & Outdoors
This fitness app can count your reps and even critique your form | VentureBeat
Rep Counter For Kettlebells Android iOS | Indiegogo