Scoring Right is a portable personal tennis score keeper. 
Attaching to your racquet and weighing less than 1.9g. YES! - it is legal to use in social and competitive tennis. The only ITF conforming racquet attachment. 
Keep score of Points  Keep score of Games  Keep score of Sets  Know from where to server at a glance; Deuce Court (right side) or Ad court
left side)  Eliminate arguments  For young and old  Affordable  Does not interfere with racquet balance  Fits any racquet  Superb adhesiveness using 3M brand  Designed to withstand extreme conditions 
Simply move the beads as your match progress and never loose focus or forget what the score is. Measurements of the units are:Large unit (points and games) is 1.9 cm (W) x 7.9 cm (L) weighing 1.35gr Small unit (sets) is 19 mm (W) x 2.9 cm (L) weighing 0.55g Both units are very thin. 1.8mm