Collars are fasteners used at the connection of soft and hard pipes. The collar addresses the issue of dead corners and leakage of liquids and gases in existing technology when used for small-diameter soft and hard pipe connections. It features an open inner and outer ring structure, secured by bolts. This collar can resolve dead corners and leakage problems at small-diameter soft and hard pipe connections, with a simple structure and easy manufacturing, costing only 30% of the original product. It is widely used as a matching part for machinery in various industries such as motor vehicles, petrochemicals, food and beverage, wastewater treatment, dust purification, and automotive accessories.