I'd thought I'd try some informal testing to get a better idea about the function of the split rings. I spooled on some Suffix Elite and hooked a lure's treble (a DTF3) to a heavy drawer's handle. The ring is normal until a certain level of pressure is reached. The pressure I exerted was a continuous,slow, steady pull; far different than a fighting fish. Sharp, hard rips did nothing. Also, the pressure it took to make the ring begin to expand was actually way more than what any fish would give you (considering 12#, anything that strong, like 30+# carp would break the line way before the ring would ever give). After it expanded it always popped back and was as strong as it was before. The ring usually stayed on lure also, minus the treble; but not every time.