B174 are not considered or listed as compatible units for the DFF1-UHD. We always recommend selecting one of the models listed under the accessories of the product, under TRANSDUCERS title. The B174L isn't considered compatible with the DFF1-UHD for certain and likely to damage one or both of the items due to over sweeping the freq and reflected signal. While the B175H wouldn't cause damage it isn't considered compatible and not sure the results one might get. Using the suggested model choices is normally the best route.