The 30B1012-5 is a red button cap accessory manufactured by Grayhill for use with Series 39 pushbutton switches, specifically compatible with part numbers 39-351 and 39-352. This replacement cap is designed to be fastened to the switch button using cyanoacrylate adhesive, providing a durable thermoset plastic construction. The cap is compatible with all Series 39 switches except the 39-2 model, making it a versatile accessory for maintenance and customization. It is commonly used in applications requiring button replacement or color coding changes on sealed and standard pushbutton switch assemblies.