Usage Tips:Heavy Duty: Made of manganese steel material, the drain cleaner combination is sturdy and durable and easy to operate. Easy To Install: It is easy to be installed on the dredging machine and the blade can be easily removed by a key insert the small hole. Fit Spring: There are two small holes under the head of the knife, which can be fit directly with the spring. Widely Application: This is a set of cutter head for dredging machine. A replacement of the drain cleaner, easily washed away the toilet or pipe plug, quickly open up the hair, grease or vegetables caused by blocking. 7 Pcs Complete Cutter Head Set: which meets your different needs. Colour:Black Material:steel Package Contents: 7PCS x Drain Cleaner Combination Cutter Heads 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.