My version is the el-cheapo, but reliable. 4 angle brackets screwed to a 18" long chunk of 2 X 12, a scrap of tubing to guide / stabilize the pin, and a rubber band for the tension spring. I replace the rubber band each time before I use the stooge.
Stooge release line is a cheap chalk line without chalk ( buy a new one, dont put the chalk in the housing, use it to mark your circle center instead), come in a handy winding reel, under 5$ for the whole stooge package, including the rubber band!