Protimeter MMS2 Salt Calibration Check Adaptor Base UOM:EACH blades and switches are the

blades and switches are the three things that actually fail on these

while staying short enough to keep the fan controllable at the tip

What the parts list says

Disposable Design

Protimeter MMS2 Salt Calibration Check Adaptor Base UOM:EACH blades and switches are theProtimeter salt calibration check adaptor The adaptor that connects a Protimeter humidity probe to the BLD4790 salt calibration check bottle. Specifications Part number BLD4790 AD Function Connects the humidity probe to the salt check bottle Compatible meters Protimeter MMS2 Protimeter HygroMaster 2 Protimeter HygroMaster L Ordered separately, and easily forgotten The salt check bottle and the adaptor are separate parts. If you have bought the bottle