Yes, that is the AA31. Please do not try to use anything else. Other triggers and wands do not hold up to the pressures put out by an engine driven sprayer and the weight of a short boom at the end. I have had the same AA31 trigger for 20 years. All I do is just overhaul it every year with the repair kit. It will even stand up to use for insecticide and fungicide application. I mention that because the boom for those treatments then sees 5 GPM at over 200 PSI. Plastic triggers are not for anything over 100 PSI.