thanks  Nandagikendan. the main issue was knowing which transducer would work with the lowrance x4 (my last post wasn't clear). it came with a skimmer transducer and for the next one i wanted to get the hockey puck style (flat bottom). Somehow first few times researching, it was never really clear exactly which transducer was right for that unit. Couple days after posting here i went back to the mfg site and all of a sudden it was more obvious than previous visits. turns out amazon has em too.