The top can spin out steel needles; Needle is 4.8cm long; The tail can spin out brown brushes, total 18cm; Hammer head: 5.2cm; Hammer head: chrome-plated copper heads, one is large, the other is small; Suitable for knocking tendon and spinning need to test skin reflex; Thicken handle increased control force while knocking; Brushes is for extra stimulation of skin reflex