Aftercare Essentials?

Wondering what are good after care essentials & would these be appropriate following a “hemi” BBL / lipo ? Also , what is the grey thing used for ?
When I had my TT I didn’t have to get anything prior to surgery regarding after care but for this one I feel like I need more things to assure best results and to be comfy . He sent me home in a faja & drains last time , a few gauze / bandages , swabs etc .