I replaced a stolen :angry BBFF1 black box to my navnet with the new DFF1 black box. Navnet is a 2006 model GP1920C. Transducer is a glassed in, thru hull, airmar 1 kw. It functioned perfect before including temperature. Sounder works perfect now with new DFF1, maybe even better. Temperature is way off. Reading about 45 degrees low, beyond adjustment range. Previous temp adjustment was 3 or 4 degrees if I remember but functioned perfect. Ducer cable was not damaged and looks fine.