The battery I ordered says 175mAh. Specs were probably wrong.

I can't answer which exactly. I bought one of these for my sprinkler control and it seems to work fine. The difference between 150 & 175 mAhr is inconsequential and will only make a slight difference in the length of back-up time provided by the battery.

There are a couple of things going on here. THe situation of either a 175mah or 150mah..has to do with capacity... this means that the one that says 175mah will provide up to 175 milli amps for one hour... If you draw less current it will last longer before recharging.. The 150 mah says it will provide up to 150 milliamps for an hour..Usually the higher the number the longer it will last before recharging is required.
The voltage you call out 9v and 7.6 volts... The one in the picture is a casing for a 9v type battery... so if you need a 7.6 v output then you can't use a 9v type . THe voltage is too high... You should call the co. that makes you sprinkler and find out exactly what you need and then buy it from them. The Bill for this is inthemail : -)