I need a new sensor cap for my Hach LDO probe?

Hach Process LDO

The LDO dissolved oxygen sensor from Hach has made measuring DO in many samples much easier. Its robust and simple to use. However you need a new cap to calibrate the unit once a year, so which one do you need?

There are three versions in common use with our customers:

The original HQ10 and HQ20 Replacement sensor cap  part Number HH/51812-00

The New HQD range including the HQ30 and HQ40 Replacement sensor cap part number HH/57911-00

Process LDO Replacement sensor cap part number HH/58112-00