15pcs bi-metal hole saw set

Features: 
1) Melded by two kinds of steel, HSS teeth and alloy steel body 
2) Cuts through stainless steel and other materials pipe, nail-embedded wood, 
hardwood floor, plywood and plastics 
3) Cutting safely and efficiently 
Specifications: 
1) Cutting depth: 1-3/8" (35mm) and 1-7/8" (47mm) 
2) 11pcs of hole saws: 
a) 3/4" (19mm), 7/8" (22mm) 
b) 1" (25mm), 1-1/4" (32mm), 1-3/8" (35mm), 1-1/2" (38mm), 
1-3/4" (44mm) 
c) 2" (51mm), 2-1/4" (57mm), 2-1/2" (64mm), 3" (76mm) 
3) 2pcs of arbors: 3/8" hex, fit 14 - 30mm; 7/16" hex, fit 32 - 210mm 
4) 1pc of extension: 12" for 7/16" shank 
5) 1pc of ejector spring