My 857¡¯s auto tuner is the excellent LDG YT-100 with LDG cable. It¡¯s designed for your rig and has same footprint. The tuner and the rig (for safe storage) both fit into one SAW metal ammo can¡ªFaraday shield. Get theses surplus large ammo cans from Midway USA or Amazon. KD4MSR
KD4MSR, Scott