
James, I haven't seen one of these but the description is:
"This Maver precision feeder rod rest has a long rubber coated metal rest that is fitted with O rings to prevent the rod sliding along it. It has a strong adjustable moulded base and is fitted with a brass thread that will fit any bankstick."
Obviously it's for fishing a feeder rod, and by the look of it the design allows you to move the rod to different positions according the where the O rings are so that you can vary the amount of bend in the quivertip.
Good luck.