What do these letters at the end of thunderbolt mean?

[ACAFan20]

Hello! These letters at the end of thunderbolts have been getting me confused for a while. Theres like 1003a, 1003asa2, 1000at, 1000bt, and 1000t. Im a new siren enthusiast and these letters at the end just confuse me a lot. I have no idea of what these mean, For example, 1003asa2, Like dude, what makes the difference. I dont even see anything noticeable -_- Plus, it just looks like federal signal slapping in random letters and numbers. Does anyone possibly know what these letters mean, Im just getting confused.

[07VFDInLCD]

I think A and B have to do with the type of motor (1-phase vs 3-phase?)

And T denotes dual tone. So Thunderbolt 1000 is single tone and Thunderbolt 1000T is dual tone. The 1003 doesn't need the T because it only comes in dual tone.

[ACAFan20]

But what does asa2 and b mean?

[ArxCyberwolf]

A = Three phase
B = Single phase
T = Dual tone
S = Series (A1, A2, B, C)

Examples:
A Thunderbolt 1000ASA2 would mean a three phase, series A2 Thunderbolt 1000.
A Thunderbolt 1000BTSAC would mean a single phase, series C Thunderbolt 1000T.

Most enthusiasts don't bother with the series designations, because they're unnecessary. The only really important details are the phase and whether it's single or dual tone. Also, don't get the single phase B confused with B-Series Thunderbolts, which are their own series.

[sirensandfirealarms]

A = Three phase
B = Single phase
T = Dual tone
S = Series (A1, A2, B, C)

Examples:
A Thunderbolt 1000ASA2 would mean a three phase, series A2 Thunderbolt 1000.
A Thunderbolt 1000BTSAC would mean a single phase, series C Thunderbolt 1000T.

Most enthusiasts don't bother with the series designations, because they're unnecessary. The only really important details are the phase and whether it's single or dual tone. Also, don't get the single phase B confused with B-Series Thunderbolts, which are their own series.

A series thunderbolts actually never had the series noted on the tag like that. The model number on A1 and A2 thunderbolt tags just says 1000A/B or 1000A/BT.