The first image precisely reflects the item that will supplied when your order is fulfilled. 2nd image shows the wiring diagram (connectors and colours). Third and fourth images shows the shape/size of the older (discontinued) version which is wider.
Dragon GTR V2, GTS V2
These dual-motor models are relatively straight forward, no specific sourcing notes apply to these models.
Note this controller suits the Cyclone (48v) which has the 8" tyres, the non-Pro model. The Cyclone Pro uses a 52V controller.
Dragon GTS and GTR (single motor, the non-V2)
These models transitioned from 36 volt to 48 volt system sometime around late 2021/early 2022.
For 36V models
BSC have listed: POWER CONTROLLER FOR DRAGON GTR AND GTS 36V ( SINGLE MOTOR)
The product image suggests this controller is current limited to 21A, which is 756 watts (derived from 36V x 21A). At full charge (42V) this would deliver 882 watts.
If you need a controller for your aged 36V system, at time of writing, that would be the most appropriate controller to source as that particular output (21A) is pretty much a custom specific order (software limited). Alternatively an 18A variant is expected to be available from eSN Feb 2024, which is 108 watts less than the original 21A). The 18A may be a better option as the chemistry in the battery cells of these older models are nearing EOL. It will also be the only option when the 21A version controllers are discontinued.
For 48V models, this one is a little more complicated, due to differences with battery. The 48V GTR delivers more power, the 48V GTR more endurance.
At time of writing BSC are not retailing any GTR or GTS controllers. Eozzie is ambiguous.
Eozzie list Dragon GTR Controller with two variants: an older and newer version. The variation is assumed to refer to the differences in voltage between the 1st Gen 36V and the subsequent generation 48V versions. Note the product images for each variation are identical (36V, 21A), there is no image for the 48V version. Given the 48V GTR has peak nameplate of 1200w with high discharge cells (~3000mAh), you can fit this 25A controller "B (Rear / Main)" in that 48V GTR model. This will deliver the full 1200w peak specification (48V x 25A) that the battery pack can accomodate.
The 48V GTS has long endurance cells (~2500mAh), this means it cannot sustain the higher discharge rates of the 48V GTR. The GTS 48V has peak nameplate of 800 watts, same as the 36V version. 800 watts / 48 or 54 volts = 15.6A current. If you choose to fit a this 25A current limited controller into a 48V GTS, configure the display/throttle P-settings to no more than 63% (or whatever you would calculate from the original controller's nameplate amp rating). Setting this limit will reduce excessive power draw that will otherwise prematurely degrade the long term health of the battery (amongst many other reasons). Mark this on the case of the display/throttle with a paint pen or similar, so the owner, or subsequent owners do not exceed this current.
eSN has non-retail 20A controllers, which could be used although again these should have their power dropped back a touch, benefit being less risk of damage from when someone up's the P-Settings.
Evolution of controller and connectors
Jinpin make incremental revisions to these controllers. For example, the earlier controllers were of different size (larger/fatter) enclosure. You will observe some variations with the wiring and number of connectors, often these have been "bolted on" for additional functionality, such as security devices and other switching instrumentation. Typically the newer revisions are "backward compatible" with previous versions. The first product image shown reflects precisely the stock on hand and that is what you will be working with. The wiring can generally be determined easily from colours and some logical thinking, with some help of the additional photos and diagrams on this product page. It is good practice to sticking the connectors down with Blue Tac adhesive and taking a photograph of the connectors, polarity/orientation and wire colours. Many of the colour conventions adopted are universal, such as the wire colours adopted on Kaabo makes.