... ,we are factory 2,TCT ,Bi-mental,HSS hole saw 3,size:14mm~220mm 4.high grade 5.t.c ... .t hole saw;T.C.T hole saw 1. 3-ply cutters reduces tip crack ... plate. 2. The 25mm effective length enables this hole-saw to drill thick steel plate as well as curved face ... . 3. The abrasion reducing design heightens durability of hole-saw to great degree,besides,with lighter and faster drilling compared ...