Exell A21PX 4.5V Battery 1306AP 3LR50 6135-99-114-1239 A133 A21 APX21 BA-1098 EN133A EPX21 PC133A PX21 RPX21 V21PX Plus Bolex H16 Movie Camera Praktica EE2 EE3 PLC2 PLC3 VLC VLC2 VLC3

The battery came earlier than expected and works fine; right voltage, right amperage. My expensive-at-the-time rack delay is back in operation. No complaints.Another user left the comment that the replacement battery for Eveready 523 (obsolete) used in many older Digitech effects units did not work for him and was "1/8in too small." I have a Digitech DSP-256XL rack unit and the missing 1/8" might be on the battery clip, which is kind-of funky; mine lost the contact from the clip due to an aging rubber insulator crumbling. Easily fixed with a small shim or a different/better battery clip and a couple of soldered contacts (this is the mod I did). Hope this helps anyone else with older Digitech equipment.

First off, the battery didn't fit perfectly, as other reviewers have noted.I needed to replace the decades-old battery in my old Digitech processor as Eveready no longer makes the 538 battery that originally came inside the unit.When I first put the new battery in, it was not a tight fit. I had to bend the housing prongs inward a little bit for the ends of the battery to make solid contact.Once I did that, the unit recognized the battery and now I can save custom presets just like the unit was brand new.Very happy to have that processor functioning like it used to!

Snapped this battery in and it fit perfectly!

I am using this battery in a non-standard application. It is being used as the bias battery in an AN/GRC-9 receiver. It works good.

I installed these batteries and they fell right out of the battery compartment. They are just a wee bit shorter than the ones they were replacing. I folded up some aluminum foil to take p the space and they worked just fine. I would not recommend them but if you have something conducting to shim the space with then they'll work.

Works perfectly in my 35 year old Electro-Voice Model PL76 microphones that required a battery which was taken off the market years ago for environmental reasons. My mics sat in a box for years unused; I never got rid of them as they were worth nothing and were still the best mics I ever owned. Now I am using them again and I am thrilled.

This battery IS NOT Compatible with the Digi-Tech GSP21 Guitar Processors. The battery is an 1/8" too short. It is NOT the same LENGTH as the Energizer 523 battery. So if you're buying it for the Digi-Tech....Keep Looking.

Fits my old Macintosh Plus perfectly. Keeps time great now. :)