Trackball Mouse Ylgf PS/2 Interface Embedded Industrial Mouse Waterproof (Ip54) , Dust Anti Violence Stainless Steel Ring Trackball Mouse Ylgf PS/2 Interface Embedded Industrial Mouse Waterproof (Ip54) , Dust Anti Violence Stainless Steel Ring
http://s.aliexpress.com/bQBJJ32Y
なんだこれはほしい（どこにつかうものなんだ