Evidently Crazypj has it figured out.
Feb. 15, I asked for an AGM battery and bought a Yuasa AGM CYTX14AH-BS (Mfg # M62H4A) at Interstate Batteries (local store) for $64.95 + tax.
Interstate calls it "CYCLE-TRON II" on the box (which has Yuasa literature in it). Also on the box is "Marketed by Interstate Batteries". ***Also on the box is "Absorvbed Glass Mat".
***They filled it on the counter as I watched and then applied a permanent seal.
That puzzled me. The guy said some come in filled and sealed and some have to be filled and sealed when put into service. He also said to never attempt to remove the seal. So, you CAN buy 'em BOTH ways.
Obviously, not all bike batteries are the same size and/or application. They don't know how soon they will sell a specific battery. So, for extended shelf life, they get their bike batteries shipped in dry.
***IF this IS NOT an AGM, then, Yuasa, and their enclosed literature, Interstate Batteries and their literature and box and the guy I dealt with have all LIED. Just one lawsuit would make all of 'em regret their misrepresentation (and they are well aware of that).
I'm convinced it actually is an AGM.
The beauty this particlar battery is 360 Cold Cranking Amps! It spins the 550 really FAST! It has never been on a charger. An "always hard to start cold" engine is now running after 3 to 6 revolutions - cold. With 360 CCA, the starter AND the ignition are BOTH getting the juice required to start the engine. What a welcome improvement!!!
FWIW, the guy said a Battery Tender would be fine to use on this battery and would be good to use if the battery had to sit for more than 3 months. Trick is, don't allow an AGM to get badly discharged before charging it.
Of course, there are other batteries and other opinions. To each his own.