Product review (5 stars): Our old dog works much better now
This was replacement part to an old dishwasher in our rental home.
It was missing, and being a fan of the good results using rinse aids, I thought I could improve the cleanliness and sparkliness of the dishes (that was lacking).  Our landlord was not receptive to purchasing a new dishwasher, as it still works.
Since the dispenser cap had been missing for years, I was unable to even fill the dispenser.  My husband reminded me that the reservoir might be full of water!  So when I received this, I put it on and waited a few months.
Then last week, I filled the reservoir with a good 6-8 oz, and I was overjoyed.  It's working well and the dishes are sparkling!!