I got this thinner boil and bite on Amazon. Fits me way better than shock doctor or the ones I’ve bought from stores and I have a small mouth. https://www.amazon.com/dp/B07P5PS1ZF?ref=ppx_pop_mob_ap_share

I use this one and love it! Super easy to fit and is very low profile. Fits so well for me that it feels like it locks into place, and came in a 2 pack so if I lose or ruin the first one I have a backup. Only down side was it didn’t come with a case.