The Belleville Washer and Collar Nut are used to reinstall the trenching blades on your TrenchBadger Pro. This is a genuine TrenchBadger replacement part. The versatile, portable trencher is designed for fast installations. Its lightweight design and portability make it easy to transport. Its powerful 1.9HP engine and carbide tip excavating blades offer full authority to dig up to 12" through the toughest soils and roots.