Thumbwheel shaft consumer electronics 500K PCB mount single turn trimmer potentiometer with SPST switch. Ideal for repair replacement or project use. 

• Device Type: Potentimeter w. switch
• Resistance: 500000 ohms
• Rotation: Single turn
• Mounting: PCB
• Case Dimensions: 5/8" wide x 3/16" thick
• Manufacturer: Not indicated
• Part Number: 1KS-B500K
• Specification: N/A
• Source: Inventory surplus

Note that this potentiometer accepts a thumb-wheel knob (not included) that is commonly seen in consumer electronics (i.e. old-style transistor radios, etc).