Striker bell is the first alarm system where you can use a open face rod and reel with the bail open. Very simple to use, place rod in holder with tip down, open bail and set depth then hang line over bell stem. When fish strikes bell rings and line can run out because bail is open.. once you use these you will get rid of the rattle reels. great product.!! Very sensitive, can be used for perch, crappies, and walleye. bell can be turned up or down to set the sensitivity of strike.