Inside pipe cutter kit installation sequence: extension rod (first) - serrated washer - saw blade - flat washer - screw (last). The screws must be tightened and reinforced! Refer to the fourth photo for example- PVC pipe internal cutter with 8 saw blades (6 blades with 1.25 inch diameter and 2 blade with 1.75 inch diameter), and screw fastening parts. Please protect the saw blade. There is a layer of protective oil on the saw blade. The saw handle is made of heavy-duty carbon steel for hardness, durability and smooth surface. The saw blade is made of strong , durable and sharp, very suitable for PVC and plastic pipes, also can be used for soft metal pipes, but when cutting soft metal pipes, please use coolant or water when cutting to prevent the saw blade from overheating. The overall length of pipe cutteris 10.5 cm(4.13 inch), and the length of the hexagonal handle is 2.8 cm(1.1 inch). The pipe cutter is suitable for most electric drills and is very easy to install and replace. Small in size and easy to carry, it is not only suitable for cutting from the outside but also for work scenarios where pipes need to be cut from the inside. Three major precautions: 1. Be sure to wear gloves and goggles when using rotary tool accessories and be aware of around you. 2. The maximum speed of the saw blade should not exceed 20,000 rpm. 3. Keep out of reach of children to prevent injury. Material: carbon steel colour: Silver Package Contents: 2 set x internal pipe cutter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is 1-3cm.