Protected Battery Recommendation for Pach/UltimateWorks Sabers

I recently purchased a few sabers and a Proffie heart from Pach Store, however it has come to my attention that the battery shipped with the heart is unprotected? It's a flat top NCR18650BD, and my understanding is only flat top batteries fit in these chassis. Can anyone please recommend a *protected* flat top battery for use in the Pach Store NeoPixel Proffie chassis?

Edit: I've measured the battery it came with to be about 65.3mm.