Oregon Bumb Knob and Spring 55-182 (Discontinued by Manufacturer)
This bump knob part is a replacement assembly for Ryobi's SpeedSpool trimmers.  The replacement bump knob will fit the following Ryobi units:  105R, 132R, 725R, 767R, 775R, 825R, and 875R.  Also fits Ryobi's SS725R add-on straight shaft.