FWIW, there are a few of these same timers. One is the Nikon MC-36 timer, for like $150. But there are several inexpensive versions. I don't know if the exact same or just an exact copy (how many such chips can there be?), but like the Neewer for example, about $17
Amazon.com: neewer timer nikon: Electronics
I have this Neewer version, very inexpensive, and it works great. Note that you have to buy the version that includes the correct camera model shutter release cord.
And a different subject, but speaking of the the camera interval timer and 30 second exposures....
All cameras that provide 30 seconds actually must literally do 32 seconds (because full stops are 1, 2, 4, 8, 16, 32 seconds).
So... if also using the interval timer, 31 second intervals cannot do 32 second exposures. It has to be 33 seconds.