https://www.swissproductsusa.com/product-page/k11-diopter-with-front-sight-and-conversion-bushings
K11 Diopter with front sight and conversion bushings | swissproductsusa
K11 Series Diopter System: This K11 Diopter System is intended for use with the Swiss K11 Rifle only, and MUST be used in conjunction with the Swiss Products...
front sightconversion bushings
https://www.philadelphialuthiertools.com/tuning-machines/conversion-bushings/gotoh-guitar-tuning-machine-10mm-conversion-bushings-black/
GOTOH Guitar Tuning Machine 10mm Conversion Bushings Black - Philadelphia Luthier Tools & Supplies,...
GOTOH Black Conversion bushings are the perfect solution for converting larger post holes to fit 1/4'' size guitar tuning machines without doweling and...
guitar tuningconversion bushings