After looking it up with the Google search engine, turns out SPS is a model of slingshot, something like Stratagem Performance Slingshot.
Also, if any of you are wondering what spalted wood is, it appears to be wood that has been affected by fungal organisms, causing changes in coloration and pattern in the wood, prized by some for its beauty. It is said that before working spalted wood, it should be put in a microwave oven and/or(?) soaked in boiled linseed oil (BLO) to prevent inhaling/ ingesting fungus spore which could have an adverse effect on one's health.
Am I the only one who uses an Internet forum to talk to himself?