I have a pair of Pro Model Da Fins.
My comparison comments are the Flex ones are so hard to insert the foot and place the strap over the ankle. Extremely tight however the same size is stamped 9-10 Med Large.
The feet are noticeably more stress free and comfortable in the Pro model than the Flex.
Specifications appear to be similar on measurement however the material used in the Pro modes is very slippery and easy to fit the foot.
The Flex model is tight and not supportive to sliding the foot into the well. It also requires a very increased effort to pull the strap over the ankle.
I imagine the different compound in the Flex model is to blame for this situation.
Can the Flex model have a ever so slight increase in the molding to accommodate an easy fitment. Understand this is probably not an option with rejiggling the machine to satisfy one model of swim fin.
Hopefully it'll stretch out, but can't see the foot well becoming more slippery to assist the foot insertion.
Overall I'm happy with my purchase and it is the fin I wanted. I'll just cop it and adjust.
Glad you sent out this survey.
Would appreciate comments from you on my findings.
Email or mobile is good. [****]