The valves can be installed singly but for maximum effect, two valves operating in a martyr valve and master valve configuration are recommended. Winged seats – the seating area is extended in the opening direction providing greater contact area with the gates. Square gates – provide greater contact area and support during operation. Titanium nitride coating gives improved erosion resistance. Optional extras: Pipework – Pairs of valve can be supplied with a joining piece of pipework welded and tested thereby simplifying site installation; Alternative ‘V’ ports – the standard 50% ‘V’ port provides excellent all round performance and is appropriate for the majority of applications. Where necessary, ‘V’ ports from 20% to 80% area, and parallel ports from 5% to 30% area for linear regulation can be selected for specific applications.