Tens 7000 Battery cover

I lost the battery cover for one of the Tens 7000 tens units in the house and wanted something to keep the 9V from falling out when it was in use so I took one of the covers I still had and re created it so now I have infinite covers

this is the model used 
https://www.amazon.com/dp/B00NCRE4GO?psc=1&ref=ppx_yo2ov_dt_b_product_details