There are three types of bonnet design: Bolted Bonnet(BB),Welded Bonnet(WB) and Pressure-sealed Bonnet(PSB) 

Product model: Z11Y.Z61Y
Nominal size: NPS3/8"~2"
Nominal pressure: Class150-800lb
Applicable medium: water, steam, oil, etc
Applicable temperature: -29℃ ~ 550℃
Main materials: A105, A182F22, A182 F304 (L), A182 F316 (L)
Standard: API 602, BS5352, ANSI B16.34
Testing and acceptance: API 598
Identification standard: MSS SP-25