What gas to use?

[Alcon H]

I'm looking to buy this pistol here:

http://www.fire-support.co.uk/product/asg-kwa-glock-g17-gbb-pistol-metal-slide

However I don't know what gas to use out of the following two:

http://www.fire-support.co.uk/product/abbey-predator-ultra-gas-700ml

http://www.fire-support.co.uk/product/abbey-predator-144a-gas-134a-replacement

Can anyone help me?

Thanks.

 

[GiantKiwi]

Ultra is the one to go for out of those, doubt the other would cycle the slide on that.

 

[AK47frizzle]

i think the 144a gas is for lower end or plastic TM gun slides. So i doubt that the 144a has enough pressure to kick back the metal slide.

 

[Rock-climby-Dave]

In that you want the Green WE Gas, stuffs awesome.