When gaming on a phone, using a gamepad adapter makes a world of difference! There are two basic types: phone clamp controllers such as the G4 Pro controller and telescopic type controllers such as the GameSir X2 Bluetooth controller (pictured). The telescopic type is more popular because the phone sits right in the middle of the controller, which is more convenient for holding long, heavy phones such as the Note 20 Ultra.
The GameSir X2 controller, seen pictured, is the wireless version of the GameSir X2 wired version that came out last year. The X2 wireless version uses Bluetooth 5.0 to connect to a phone rather than via USB-C connection. The GameSir X2 Bluetooth version looks virtually identical with the same ABXY layout and asymmetrical joystick design, although the X2 Bluetooth version is larger so, it can accommodate larger phones up to 173mm long. The GameSir X2 wired version can only accept phones up to 163mm. 
The d-pad, face buttons, shoulder buttons and trigger buttons are all responsive and have a clicky actuation, especially the shoulder/trigger buttons, which make a loud clicky noise. The trigger buttons are digital and not analog; hence there is gradual feedback, which is useful for gradual acceleration in racing games. The X2 joysticks move freely and have red and cyan blue accents that compliment the grey color scheme. The joysticks can be pushed down to activate the L3 and R3 buttons.
The top of the joysticks are rubberized, as well as the side clamps, which keeps the phone from sliding out of the cradle. Functionality wise, the GameSir X2 Bluetooth version is more versatile than the wired version because it supports both controller games (via Xinput) and games with on-screen button overlay, which are touch screen games that aren't compatible with controllers such as Call Of Duty Mobile, PUBG Mobile and Genshin Impact.
The GameSir X2 Bluetooth version also supports Apple Arcade games, MFI games and cloud gaming platforms (e.g. Xcloud, Stadia). The X2 Bluetooth controller does not support Egg NS Emulator. There is no headphone jack either; hence no headphone support. There is a screenshot function though, as well as source volume control. The GameSir X2 Bluetooth version also benefits from a rapid-fire-attack mode to execute several button presses at once.
Another new feature you get with the new GameSir X2 Bluetooth version is a proper crosshair d-pad, which is tactile and has a centre pivot. The GameSir X2 wired version uses a split d-pad with four separate buttons, which works well too because it prevents accidental presses and provides more precise control. Split button d-pad works great for puzzle/platform type games. For fighting games though, a d-pad makes it easier to execute combos.
Under the hood, the GameSir X2 Bluetooth version integrates a 500mAh rechargeable battery, while the GameSir X2 wired version doesn't because it uses the phone's battery to power up. There are two power-saving modes that will put the gamepad in sleep mode to preserve battery. The power-saving modes kick in automatically and cannot be disabled. 
One power saving mode kicks in after 5 minutes when the X2 gamepad is not connected to a device. The second power saving mode kicks in after 10 minutes of inactivity when the gamepad is connected. The GameSir X2 Bluetooth version rechargeable battery can accept a maximum 15W fast charge via 5V/3A, taking just 25 minutes to fully charge.
Because of the battery and larger size, the GameSir X2 Bluetooth version is a little heavier, weighing 186 grams, compared to 167 grams for the wired X2 version. The GameSir X2 Bluetooth version measures 13cm long, 12cm wide and 3cm high so, it's a little bigger too than the wired version, which measures 18cm long, 9cm wide and 4cm high.
The GameSir X2 Bluetooth version works with newer Android (9.0 and higher) and iOS (13.0 and higher) phones. The included extra jostick grips are a nice touch to beef up the stock ones. The joystick grip covers are easy to remove and install. The plastic back panel of the GameSir X2 Bluetooth version also has ergonomic rubberized back sides for grip. The charging cable included is also Gamesir branded.
The main selling point of the GameSir X2 wired version is wired connection, which creates almost no input lag. The only drawback though, it's the awkward placement of the USB-C connector. The X2 Bluetooth version uses wireless so, it works with iOS phones too. That said, there is a bit more input lag (10ms), although it's not too noticeable. The GameSir X2 Bluetooth version does not work with PC.
To sum up, the GameSir X2 Bluetooth version new features are cheaper price, iOS support, larger cradle, more games supported, screenshot function, rapid attack mode, crosshair d-pad, replaceable joystick rubber covers and a hardshell case, which the wired version does not come with. The hardshell carrying case has a solid frame with rugged fabric material on the exterior that repels water. The zip has concealed teeth, as well as dual sliders with rubberized pullers. The X2 carrying case has GameSir branding on the sliders and top of the case via a sticker. The inside of the case is lined with soft microfiber like material and features a netted mesh pocket and a non-removable elastic band that straps the gamepad down. You can buy the X2 Bluetooth controller from GameSir and Amazon.
