Has a locking collar and a spacer to use with slim barrels.
Inside is a clar plastic tube through which the ball travels. A pair of IR emitters on the board send a beam through to the receivers on the other side of the tube (shown with white, blue and purple wires connecting them to the board). As the traveling ball breaks each beam, the microcontroller measures the time between beam breaks and thus computes the velocity.
There's no screws holding the shell together, just glue. You'll need to carefully use a knife blade or large, wide screwdriver to crack it open. The board is held to one side of the shell with 3 tiny screws (if you look closely at the pic, you'll see I've already managed to lose one of them). The two black thingies on the board are the IR emitters.
Two soft rubber pushbuttons and a small LCD display are on the other side of the board.
This is the button and LCD side of the board. You can see the two button contact spots on the left, and the two rows of solder pads for the LCD.
Component side. Unfortunately, the chips aren't labeled (U1, U2 and so forth). The two little 3-pin SMT devices at the lower right would appear to be transistors that the IR receivers connect to.
Top 2 chips and center chip:
(serial-in, parallel-out shift register)
large microcontroller on far left:
(4k ROM, 128 byte RAM, 80C51 based, running at 4.00 MHz)
Bottom right chip:
National Semiconductor LMV324M
(general purpose, low voltage rail-to-rail opamp)
Note that the opamp originally had this sticker on it: