还记得这个箭头吗，不记得补一下这个视频

经常会碰到钻不用的孔，频繁换钻头的事情，现在有一种多级钻头，可以免更换完成多种孔径的钻孔工作，威力和兰博的箭头一样巨大。

Product features

• Condition: Brand new. – Material: High Speed Steel with durable Cobalt Coat

• This one set replaces 50 individual drill sets. Comprised of high quality, long life high speed steel.

• Self starting – no need for a pilot hole. Cobalt coated to reduce friction and run at cooler temperature.

• Automatically deburrs holes as you drill.

• Package includes: (1) 5 piece drill set. (1) carrying case

Product description

Specifications: 1/4” to 1 3/8” Drill Bit: 10 Steps (1/4”, 3/8”, 1/2”, 5/8”, 3/4”, 7/8”, 1”, 1 1/8”, 1 1/4”, 1 3/8”). 3/16” to 7/8” Drill Bit: 12 Steps (3/16”, 1/4”, 5/16”, 3/8”, 7/16”, 1/2”, 9/16”, 5/8”, 11/16”, 3/4”, 13/16”, 7/8”). 1/4” to 3/4” Drill Bit: 9 Steps (1/4”, 5/16”, 3/8”, 7/16”, 1/2”, 9/16”, 5/8”, 11/16”, 3/4”). 1/8” to 1/2” Drill Bit: 13 Steps (1/8”, 5/32”, 3/16”, 7/32”, 1/4”, 9/32”, 5/16”, 11/32”, 3/8”, 13/32”, 7/16”, 15/32”, 1/2”). 3/16” to 1/2” Drill Bit: 6 Steps (3/16”, 1/4”, 5/16”, 3/8”, 7/16”, 1/2”). Aluminum Case Dimension: 6” x 4” x 1 1/2”. Instruction is not included