Quick change tool post for lathes. The set comes with 7 standard holders, 1 parting holder and 1 Boring Holder. The main block is 3″ square by 2″ high with a 5/8 bore. 1 mounting block 72 x 72 x 51mm. 1 Parting Holder For 5/8″ Blade(Parting Blade Included Of Size: 3/32 x 5/8 x 5″). 1 Boring Holder With “V” To Support Round Tools Comes Complete With Spanner. All the parts are hardened and ground.