The Slim Line 2 is a spring loaded clamping device with inter-changeable windows.

The Slim Line 2 fits your machine with an adapter bracket and intended for single head machines.  Once installed, all you do is open the clamping window by rotating the handle down. Insert what you want to sew and release the clamp.  

The Slim Line 2 gives you the option of using larger window sizes when needed.

Each window sets consists of three pieces.