These types of valves can be delivered in different configurations, and they all have in common two on/off valves in series with the possibility to bleed in-between.

This type of valve configuration will cover both industrial and API standards with regards to DBB(double block and bleed) and DIB(double isolation and bleed) requirements​

Combinations could be:

Two Gate valves in series with needle bleed, two ball valves in series with needle bleed, quill for injection, two ball valve in series with needle bleed and integrated check valve, gate and globe valve in series and needle bleed. Option for soft seated or metal seated for all varieties.