Bass Drum O's 4" White round HW4

I cut a perfect circle... followed the instructions to the letter... but it was impossible to snap the female ring under the male ring... halfway yes but once I reached the opposite side of the ring the part that was snapped in jumped out... over and over again... until the female ring broke... I hope the male ring keeps sticking against my drumhead because it looks good and my bass drum never sounded better now that I have a porthole.

I decided to cut out a port hole for my BD. While the hole could stay just bare after cutout (it was a perfect cut as I used a special cut out tool for port holes) i thought it would be a good idea to put a hole reinforcement ring in place. I would not want to risk any skin cuts.
First thing to note - I was sent a Gibraltar brand O ring, I had not clue this was Gibraltar brand, it simply does not say in description. I thought I ordered another brand. Anyway, it works nevertheless.
Secondly - It took a bit of persuasion to keep the ring in place. Some other drummers mentioned this even in their product reviews on the website. I put mine on the head after cutting out a perfect hole. Then applied the ring and pressed with my hands. One part went in OK, second part kept jumping back but eventually stayed in place ... for 24 hours, then it jumped out again.
Through trial and error I've learnt that to apply this ring correctly one needs to use more focused pressure and so on day two I used my pedal beater, specifically the other side of it, the rod, and pushed on the ring's part that kept jumping out. This, when done carefully, works like a treat. Now the ring stays in place as expected.

4 stars only because description did not state the brand