The HI73127 is a spare pH tester electrode that is compatible with:
HI98129, and HI98130 Combo multiparameter testers
HI98127 and HI98128 pHep® testers
HI98121 ORP tester
These meters also use HI73127 replaceable electrode that has a stainless steel round connector and extendable cloth junction. This cartridge design has no pins to line up or that can break.