Retail 1.50 each Part Number HB-HHB. This In-line 30 Amp Fuse Holder is a perfect solution for so many RV/Trailer wiring applications. They are rated for 30 amp at 32 volt. They have a Nylon Body with tin-plated copper contacts. They accept 1/4 inch Round fuses from 7/8 to 1 1/4 inches in length.