Prevent debris from adhering to the prism surface
The US-α prevents debris from adhering to the prism surface of the PRM-100α, PRM-2000α and CM-800α. As with other fittings, it can be affixed in the piping system.
More Info:
https://www.atago.net/product/?l=en&f=products-prm-top.php#DCN48410