The OP had a fuller statement about this on this forum a couple of weeks ago.
I just spoke with a representative at Teknetics who informed me that there are now 4 variants of this detector. Push in connectors with 1/4" phone jacks are fairly recent and are sold through sporting goods stores only. Screw in type with two phone jacks are available through Web outlets like Amazon and eBay.
Mystery solved.
The have never been more than two versions of coil connector on First Texas (Fisher, Bounty Hunter and Teknetics) detectors.
The so called "push-on" connector has male pins on the coil's cable connector and the detector has a female receptacle - there is no locking collar.
The so called "screw on" connector has a female connector on the coil cable and the receptacle on the detector has male pins. This type of connector also "pushes on" but has a metal locking collar which screws down after the connector is pushed on.
Both types are currently in production and the detectors are functionally identical.
Independent dealers (many of whom are forum sponsors) sell the version with the the locking collar - another good reason to deal with them.
The version with "push-on" connector is sold by mass market outlets and national retailers.
As far as there being 4 different versions of the Delta, that is the result of there being different headphone connectors - the 1/4" (6.35 mm) and the 3.5mm. Some Deltas have had both types, some only one. Over the production run, some detectors have had both receptacles, some only the 3.5mm.
All in all, not a big deal. Lots of choice of additional coils of both types available, even adapters to use screw on coils on push on detectors. If your detector's headphone socket os the wrong size for your phones, an adapter is about $3.
