The Top-Flo® manual bonnet incorporates a simple mechanism to adjust diaphragm squeeze which greatly enhances diaphragm life span. The adjustable close stop incorporates a sliding shaft/set screw design for ease of setting with only simple tools needed. No hand wheel removal or additional caps or gears to set or reinstall. for applications where contamination is of concern, "09" stainless bonnets are dual Viton® 0-ring sealed as standard. Viton® o-ring seals in the hand wheel and stem areas prevent contamination from entering through or exiting from the bonnet in case of diaphragm failure and prevent wash down fluid ingress.

All bolts used with the style bonnet are fully encapsulated when installed without the use of additional plastic caps or plugs to eliminate external entrapment areas. When Top-Flo® new style bonnets are used on block style valves, acorn nuts compliment the fasteners to ensure no exposure to bolt threads.