I would like to buy an attenuator for my DRRI, wich one you suggest me to buy?
None. Try the THD Yellow Jackets instead and crank your amp.
weber mini mass 25 watt. $75 from weber. that's what i used with my drri. i sold it because i love the loud cleans better, and use fuzz for dirt.
Weber is good but you certainly dont want the 25 watt for a 22 watt amp. You need the 50 watt attenuator. Unless frying amps is your pass time