The Echo 21041752730 OEM Wing Stud is a part that fits various Echo models, primarily those related to the intake and exhaust systems. The specific models and serial numbers include a wide range of equipment from small handheld blowers, trimmers, and other lawn and garden tools. Some of the models that use this part are:

• EDR-260, ES-210, GT-2000, GT-250, GT-201, HC-150, PB-200, PE-200, and many others, with serial number ranges noted for each model.

The wing stud is likely used to secure components such as the intake and exhaust, air filters, and fuel systems. If you're unsure whether it fits your specific Echo model, checking the serial number ranges listed in the compatibility list will ensure proper fitment.