So, I know this is an old post, but I have a Shinp SL-5 50mW 532nm unit and thought I'd throw my 2 cents in the ring in case someone in the future searches for information on an ebay unit or something. I have since disassembled the unit and utilized various bits elsewhere on other projects and such...
So, about a decade ago we used a few SL-5s in a haunted house (knowing what I do now about these things..... probably wasn't the smartest thing to do). They are indeed pretty solid. There are two boards inside, a 2 channel laser driver with adjustable outputs, and a 'brain board'. The brain board contains a Nuvoton w78e058ddg MCU to read the DMX signal, monitor the mic for sound activated mode, and, via a 2805 Darlington chip, drive a pair of stepper motors. The power input runs to an internal transformer (no chassis ground, but does have an input cap and fuse holder built into the plug housing) which outputs 2 voltages ~11Vac and ~8Vac, with the brain board consuming the 11V feed. Both boards have a KBP206 FULL BRIDGE RECTIFIER!!! ...as the first component and seem to have decent, though bare minimum component count, design. Its obvious they use the same hardware from the dual head models as this single head unit, as the brian board has an unpopulated 2805 foot print, a mystery foot print, headers labeled "RED" and "BLU" along with "GRN" for TTL input control on the laser driver, and another set of headers in parallel for the steppers (I imagine the dual head mirror output does the same patterns from both sides). The steppers are standard 5wire 1.8° MSY 39BYG101-1, though they do have a 6 pin plug, so if you're good at soldering tiny wires you can separate the coil center taps. The mirrors seem like decent (as in acceptable, not you're getting a diamond in the rough bargain) first surface mirrors, they're sort of press fit into their aluminum mounts utilizing the blue film covering to help hold them in, no coatings and the silvering will scratch VERY easily.
The laser seems to be a (possibly dual side, though most likely end) diode pumped solid state module with a (technically) adjustable front lense. I have no idea if the crystal is YAG or YVO4, but I've passed the emitted beam through 1000l/mm diffraction film and the spectra appears to be about spot on for 532nm (give or take my measurement inaccuracies).
The big problem with these green lasers is .... say it with me kids .... No IR filtering. Like...at all, it seems. There isnt an extra bright spot immediately obvious using a cell phone camera or DSLR when checking the spectra with diffraction film. However pointing the camera 'down the barrel', if you will, and sliding to the side there is a clearly noticable pinky-white output at a certain angle (do not recall the angle/wavelength off my head, I'd have to measure it again) that does coincide with the 'below red' side of the diffracted light.
The good news is this little module can take a licking and keep ticking. I have been ballsy before and walked up the trim pot, this thing is capable of outputting A LOTA more than what its set at from the factory, and even that is fairly bright (When I do use it, it is turned down...of course, as mentioned there is still going to be a ton of IR...yes, I have goggles). Turned up though (I do not have a laser power meter unfortunately, (anyone around inland SoCal wanna meter my crappy salvaged laser head?) somewhere around 3/4 on the trim pot, I'd measure the current but the battery pack I use it with is currently charging), through a cheap cell phone clip on macro lens it cuts black electrical tape. Not incredibly fast, but it does it. The driver also leaks a bit of current so there is a helpful little dim red light in the back of the laser even if turned all the way down or 'disabled' via TTL to let you know you shouldn't be looking at it.....so that's fun.....
Should you get one? Sure, especially if it's on the cheap. The patterns are kind of generic (all pre programmed, you can fiddle some things like circle or square dimensions but there's no direct XY control), however it does have some neat bits inside to flesh out your parts bins. I'd advise against using anywhere the beam might reach peoples eyes, or be near the beam path....or anywhere people care about exposure to a IR leaky green laser....