Yeah I like Scubapro single hose regs. S.P.E.C. or SPEC is not just the little AP bleed holes found in many of Scubapro's regs. It stands for Silicone Protected Environmental Cap. This SPEC cap (filled with liquid silicon) was an early Scubapro innovation that was created to make SP regs less prone to freezing in cold water. Below is a MK 200 that has the actual SPEC rubber boot on it, the MK 200 is basically a MK 2 upgraded for cold water conditions with a SPEC AP cap and also the addition of A RUBBER BOOT to assist in keeping the AP chamber clean of detritus.
1988-MK200-SPEC-BOOT-(6).jpg
This became a standard option for all MK 2s afterward and Scubapro stopped using the MK 200 designator. The 1993 MK 2 pictured shows the groove for the SPEC BOOT, but has no actual S.P.E.C. AP cap on it.
1993-MK2-(3).jpg
The rubber boot groove was added in 88. A true S.P.E.C. has the AP holes as shown in the 1981 MK2 reg.(see 1981 MK 2 SPEC)
1981-MK2-SPEC.jpg
This feature was available on the MK 5 and 10, I believe, back to the early 1980s or even before.
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