According to the customer demands to make the goods. 

Material: Alloy-Steel of High-Quality 
1) 38CrMoAlA(JIS SACM645) 
2) 42CrMo(AISI 4140) 
3) Cr12MOV(JIS SKD-11) 
4) 4Cr5MoSiV1(JIS SKD-61) 

Heat-treatment: 
Nitriding treatment 
Electroplated hard-chrome 
High-frequency quenching 
Spray coating Bimetallic-alloy 

Types: 
Screw can be mated with different heads of screw, barrel 
Can be mated with different sprinkler heads.