Gravity automatic clamp base can be used on ALPHA7500 stringing machine. Compatible Machine - 12.2mm hole in the sleeve, and the length of the sleeve just allows the clip to spring out automatically. This gravity automatic clamp base can shorten the threading time. Easy to lock the base handle, does not require a relatively large force. When the clip is dropped, simply unlock it or press a button on the clip to unlock it. Random lettering, don't accept the specified lettering. Colour: black Material: aluminum alloy Package Contents: 2 x Gravity automatic clamp base Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.