I know, I know... seems fake.
But it’s definitely a real thing we sell on Amazon. Promise.
Here’s the compat info per amazon.
It’s an adaptor that converts a 2.5mm headset to an RJ9! It is only recommended from amplifiers. Customers trying it through the headset jack are doing so at their own risk!
Here is a quick compat guide from Amazon:
** Functions best when paired with an amplifier.
This list (updated 10/1/2016) is not all inclusive. Please look up the specifications on your specific phone to see if it has a RJ9, RJ10, or RJ22 headset jack. Please let us know if you find more compatible phones or incompatible phone models.
Avaya 2410, 1600 and 9600 series
Nortel 1140T and Visa 350
Uniden Dect2088, TRU9496
AltiGen IP Phone 500, 510, 600, 705, 710, 720
Avaya 4600 Series IP
ESI 48-Key IP Feature Phone and 48-Key Digital Feature Phone
GE Model 2-9451
NEC Dterm Series E
Norstar T7316E, M3904
Nortel IP, Nortel IP – 1230, Nortel Meridian Norstar Northern Telecom
Shoretel ShorePhone IP models
Talkswitch IP Phone, TS-600
Plantronics S-12, M22, A20, MX10, TSB, AP15