For a show I'm doing I would like to use gobos for a night forest scene. However, I'm not sure how this type of gobo holder works! (I've only used the square kind) I did some searching but I could only find them for sale and no instructions. The fit inside the S4 Jr but they seem to small - they slide in all the way to the handle and then wiggle around inside the fixture. Something tells me that isn't right. I've also tried them in my S-C Lekos but the same thing happens - it doesn't secure. These are going in a S4 Jr Zoom. I know these are not B sized gobos, but I'm not sure they are M sized gobos. The gobo is 2.5 inches in diameter - is that size M? At the widest point the holder is 2.75 in wide.