Scoring Right is a portable personal tennis and paddle score keeper. Attaching to your racquet or paddle and weighing less than 1.9g. YES! - it is legal to use in social and competitive tennis. The only ITF approved conforming racquet mounted scoreboard Keep score of Points/ Games / Sets Know from where to server at a glance; Deuce Court (right side) or Ad court (left side) Does not interfere with racquet balance Superb adhesiveness using 3M automotive grade adhesive Designed to withstand extreme conditions Simply move the beads as your match progress and never loose focus or forget what the score is. Keep safe by having your personal scoreboard, eliminating the need to use public court side scoreboards and score tenders. Large unit (points and games) is 1.9 cm (W) x 7.9 cm (L) weighing 1.35gr Small unit (sets) is 1.9 cm (W) x 2.9 cm (L) weighing 0.55g Both units are very thin. 1.8mm