Thanks for the info... I just ordered one pre-packed filter for the Bauer P21/X21 and one for the Alkin P21/X14... The Bauer was $37 and the Alkin was $45... Ordered from Filtertechs. So, I'll have them side by side to compare and will post my results here. I'll be using them on my Alkin Vertical W31.
The Freedom and Simplicity of Vintage Equipment and
Vintage Diving Technique are Why I Got Back Into Diving.