Because of shallow, well-spaced under-ribs and a leakage distance in excess of standard duty requirements, this design performs well in areas of mild contamination.

A design with a longer leakage distance than the standard profile obtained by two or three ribs of greater depth. The profile and wide spacing of the ribs promote an effective self-cleaning action by wind or rain.Their wider spacing also prevents arcing between adjacent ribs under severe contamination.

The absence of deep under-ribs on this shell type greatly reduces pollutant accumulation on the lower surface because air flow is smooth and uninterrupted.
This design is particularly effective in desert areas where natural washing by rain is infrequent. It is also effective for tension (dead-end) strings in extreme industrial pollution and can solve ice-bridging problems when alternated with other profiles in a string.

This spherical shape permits a leakage distance equivalent to that of standard profile type. The absence of under-ribs reduces pollution build-up, notably in dust-laden environments. Manual cleaning, if required is easy and efficient with the spherical profile.

A design with a leakage distance equivalent to that of anti fog profile type.
Elimination of under-ribs reduces pollution build-up, promotes self cleaning and facilitates manual cleaning when necessary.