Quiet Glide QG.FR1300.HK5.08 Flat Rail Hook Strap Style Rolling Door Hardware Kit with 5" Roller - Black - Fits Doors Up to 1-1/2" - All Questions

Hi, I'm shopping for a steel barn door kit 60", what grade steel is this kit? Would you recommend it for installation in a bathroom, is it corrosive/rust proof? Also, do you happen to have something in stainless steel? Thank You