I have 7 al 80’s and 2 are neutral 80’s I will not put them on my back I use them for filling lift bags. I use steel tanks to dive with, I have 2-80 4- 100 and 2- 120’s all are hp and all are din. I would never buy another alu. tank to go dive with they float when empty and are for beginner divers. And when was the last time you heard of a shop that could not fill a HP. Why carry all the weight of a lp when you can carry more air with hp.