Features: l Made of high quality material, durable and wear-resistant l Nice replacement for broken or old one, make you device work properly l High quality for professional use l Easy and convenient to install and remove Specification: l Types: One Small Knob/One Middle Knob/One Large Knob/One Set Of Zoom Knob One Button Shuttle/Middle Knob Plus Plastic Ring(Optional) l Applicable Model: for DPO MSO TPS TBS MDO TDS-BC Series Package: l One Small Knob or l One Middle Knob or l One Large Knob or l One Set Of Zoom Knob One Button Shuttle or l Middle Knob Plus Plastic Ring