Product description 1.[HIGH-QUALITY MATERIAL]: Hole Saw Set is made of Carbon Steel, its surface is treated with Black Oxidation. Black oxide provides mild corrosion protection to the treated parts, it is primarily used because of its aesthetic properties. 2. [High-Precision Performance]: The special gear design makes the hole more accurate and symmetrical for faster and cleaner cutting, impact resistance, wear resistance 3.[ATTENTION]: This hole saw kit is NOT suitable for HARD materials, such as density board, hardwood, metal. It is ideal for soft materials, such as plastic plate, thin pvc board, plasterboard, softwood, your ideal choice for DIY projects and household maintenance and repair 4.[11PCS SIZE INCLUDES]: 3/4"(19mm), 7/8"(22mm), 1-1/8"(29mm), 1-1/4"(32mm), 1-1/2"(38mm), 1-1/3"(44mm), 2"(51mm), 2-1/2"(64mm). 5.[16PCS SIZE INCLUDES]: 3/4''-5 (3/4 " (19mm), 7/8" (22mm), 1-1/8" (28mm), 1-1/4" (32mm), 1-1/2" (38mm), 1-3/4" (44mm), 2" (51mm), 2-1/2" (64mm), 3" (76mm), 3-1/2" (89mm), 4" (102mm), 5" (127mm). 6. [EASY ORGANIZATION]: Set includes the hole saw kit holder with size index for easy storage and organizing. It is designed to keep all components organized and convenient to take. Specification Item: Hole saw set Material: Carbon Steel Cutting Depth: 20mm Package Includes 11pcs: 8x Carbon Steel Hole Saw 2x Mandrels 1x Hex Key 16pcs: 12 x Carbon Steel Hole Saw 2 x Mandrels 1 x 2.5mm Hex Wrench 1 x installation plate Notes 1. When using, wear protective goggles and gloves. 2. Not suitable for hard material such as density board, aluminum, stone and computer tables. 3.After the use of a few anti-rust oil on the surface of the filter to avoid natural oxidation, can improve its service life. 4. Hole saw are suitable for wood, if you need hole saw set for metal please find a thicker hole saw set. 5. In order to prevent rusting of the drill bit, oil is required after production, and some products will be stained with oil on the surface, which will not affect the performance of the product. Please rest assured and use it normally. 6. Drill bit must be installed to drill relief holes to make saw work easier. It's recommend using machines with drill speed less than or equal to 500 rpm, which can prolong the life of the hole saw.