I have to chime in again and say that you really need to consider do you want to use a detector unless you have verified it is compatible with the panel?  Did you check the installation instructions to see if the detector is on the list of 2 wire detectors for the panel you have?  
This is life safety and you do not want to have a situation where the detector does not operate because of a compatibility issue.
		
		
	 
Agreed. And yes, they are listed as compatible.
View attachment 3159
		 
		
	 
Steve the System Sensor Detectors with sounders are NOT on the list as compatible.  I thought that was the detector in question.  If I am mistaken sorry.
		
 
		
	 
Yea but that doesn't seem to be compatible with any system looking at the charts. While I can't swear to it, the only difference in the two is the sounder and I fail to see how that would make it incompatible except if the current draw from the sounder would overload the panel or something which I don't think it would. Of course HAI would have to say this for sure but I don't see anything wrong with it. Elk only states the same non 'A' model as compatible and my existing 2WTA-Bs work fine.
		
 
		
	 
I have the system sensor specs for the 2WB and the 2WBT-A at work.  I am 99% sure the specs are NOT the same.
The System Sensor Detector with sounder is compatible with the following per the System Sensor website.  I know for a fact it is incomplete since I personally had UL test this detector with several panels a few years ago that are not on the list.  
2-Wire Compatibility for System Sensor Model 2WTA-B
Manufacturer	Panel Model Number
ADT 	Focus 200P, Focus 200PA, Focus Cadet, M302MADT, Safewatch Pro 2000, Safewatch Pro 3000, Unimode 10, Unimode 10UD, UNIMODE 200, Unimode 5, Unimode 5UD
Amerex 	SR-X, SR-XE
Ansul 	AutoPulse 542D, AutoPulse 542DE, AutoPulse 542R, AutoPulse 542RE
Chemetron 	Micro-1011, Micro-1011E, Micro-1012, Micro-1012E
Detection Systems 	DS400i, DS400M, DS7080i, DS7080iP32, DS9422
DSC 	CFP-102, CFP-105, P832, P832DL, PC5010, PC5015
Faraday 	12400, 13200, 13400, 15220A, 15240A, FIREWATCH - 200, FIREWATCH - 400, FIREWATCH - 4000, FIREWATCH - II+2, MPC-2000
FCI 	AMM-4S, FC-10C, FC-2224, FC-4224, FC-5C, FC-6324, FC-73, MMI-6S
Fike Corporation 	GP-10UD, GP-5, GP-5UD
Fire-Lite 	M302, MMF-302, MMF-302-6, MP-24, MRP-2001, MRP-2001E, MRP-2002, MRP-2002E, MRP-4424, MS-10UD-3, MS-10UD-3E, MS-10UD-7, MS-10UD-7C, MS-10UD-7E, MS-2, MS-2410B, MS-2E, MS-4, MS-4424, MS-4424B, MS-4E, MS-5024, MS-5024UD, MS-5210UD, MS-5UD-3, MS-5UD-3E, MS-5UD-7, MS-5UD-7C, MS-5UD-7E, Sensiscan 200, Sensiscan 2000
First Alert 	FA1220CV, FA1340C, FA148CP, FA1500C, FA1600C, FA1600CA, FA160C, FA162C, FA1660C, FA168C, FA168CPS, FA1700C, FA2000C, FA2100C
Gamewell 	Flex 4, FLEX 405, FLEX 620, Flex 8, FS140
Gamewell-FCI 	AMM-4SF, Flex GF505, Flex GF510, MMI-6SF
Harrington 	HS-2100, HS-2200, HS-2402, HS-2800, HS-3030
Honeywell 	TC841A1000, XLS-MM-Z, XLS140-2(E), XLS3000
Honeywell Security (Ademco) 	4140XMP, 4140XMPT, 4140XMPT-2, 4209U, 5110XM, 5120XM, VISTA 128B, VISTA 128FB, VISTA 15, VISTA 15P, VISTA 20, VISTA 20BAY, VISTA 20HWSE, VISTA 20P, VISTA 20SE, VISTA 32FB, VISTA 40, VISTA 50, VISTA 50P, VISTA 50PADT, VISTA 50PUL, VISTA A, VISTA AMT3, VISTA CN, VISTA HW, VISTA PULADT
Johnson Control 	IFC-320(E), IFC2-3030(E), IFC2-640(E), M302MJ, M502MJ
Mircom Technologies Ltd. 	FA-1008KA, FA-1012KA, FA-101A, FA-101U, FA-1025A, FA-1025U, FA-102A, FA-102U, FA-202, FA-202U, FA-204E, FA-204EU, FA-2600, SGM-1004A
Napco 	FW-C2Z, FW-C4EZ, FW-C4Z
Notifier 	AFP-100, AFP-1010, AFP200, AFP400, AFP600, AM2020, FZM-1, NFS-3030, NFS-320, NFS-640, NFS2-3030(E), NFS2-640(E), NZM-100, NZM-100-6, RP-1001, RP-1002, RP-2001, RP-2001E, RP-2002, RP-2002E, Sensiscan 2000, SFP-1024, SFP-10UD, SFP-10UDC, SFP-10UDE, SFP-2402, SFP-2402E, SFP-2404, SFP-2404E, SFP-400, SFP-400B, SFP-5UD, SFP-5UDC, SFP-5UDE, SGL-2000, System 500, System 5000, XP TRANSPONDER, XP6-MA
Radionics 	D7022, D7024, D7024 or DS9400, D7212, D7412, D9112, D9412
Secutron 	MR-2602, MR-2605, MR-2616, MR-2900
Silent Knight 	5204 Mfrd after 01/2002, 5207 Mfrd after 7/1995, 5820XL, 5895XL, IDP-Zone, IDP-Zone-6, IFP-1000, RPS-1000, SD500-SDM, SK-2, SK-2224, SK-2E, SK-4, SK-4224, SK-4E, SK-5208, SK-5UD, SK-5UDE, SK-6324
Summit 	SFC-102
System Sensor 	2W-MOD2, M502M, PDRP-2001, PDRP-2001E
Viking 	PAR-4, PAR-4E