We have learned much from the 30mm and we have made many corrections on the 37mm to improve an already great product. For starters the tolerances are much tighter so the slight chimney wiggle the 30mm had is completely gone. 2nd we tightened up the side airflow making the airflow control more effective. With the 30mm you had to use certain coils for it to preform as expected, with the 37mm we have tested coils from 3.5mm all the way up to 6.5mm and it has preformed perfectly. 3rd the seepage from the seams from refilling has been eliminated completely by adding lips to the tank sections so a more secure seal is made when assembled. 4th we switched to flathead screws to help with stripping screws with hex screws. With this 37mm we suggest using dual 6mm staggered coils from Ohmcentric coils or k9 coils. Both of these gentlemen are highly knowledgeable in coils and can help you with any needs you may have.
The 30mm was our very first tank and we have learned a ton from positive feedback from the community. The 37mm def tank I'm confident is going to be one of the best 30+mm tanks on the market. Its just absolutely perfect.
If you have any issues with your tank please email me or join our fb group. More then happy to help dial your tank in with you!
fb group - https://www.facebook.com/groups/defheads