REPLACEMENT TRACKBALL x 2 - Designed for any trackball mice using 1.34 (34mm) trackball size; Such as from Perixx: PERIMICE-517, PERIMICE-717, PERIMICE-520, PERIMICE-720, Logitech: MX Ergo, M570, M575 Cordless (not include Trackman Marble), Elecom: M-XT3DRBK (EX-6), M-DT2URBK, EX-G/DEFT Sanwa: MA-WTB43BK | BASEBALL AND SOCCER DESIGN - The novelty design of baseball and soccer on the trackball. The quality and unique design of your favorite sports can be felt on your finger tip, and it provide a fun and different desktop for yourself and love one. This is also a perfect gift for your love one who likes the baseball and soccer. | GLOSSY FINISH - The glossy surface is treated with a special coating to provide a precise and smooth tracking performance; The matte coating trackball specializes in precise pointing and movement, ideal for long documents, excel, and handling of mass data processing. | HOW TO USE THE TRACKBALL - Please remove the existing trackball from the trackball mouse with the finger or pencil from the bottom of the mouse, and insert the replacement trackball to the same location. If the initial movement is not smooth, please remove it and rub the trackball for 15 to 30 seconds. All replacement trackball comes with a special protection coating, and it may disrupt the tracking of the sensor for the first time use.