Umarex HDP50 Dual Air Tank Function Test compatible with most Umarex markers 

this is the test for the duel air setups i shown in the facebook group, it works on the hdb68 hdr50 hdr68 hdp50 and compact watch till the end and see my conclusioni learned a lot today about this build and there is important info near the end. forget all my trouble shooting in the video just go to the end, you can still use co2 and hpa just make sure not to use a self purging asa on off, or you will have to use that tank first