The disclosure provides a device for fine weight adjustment of a host apparatus. The host apparatus can be a free weight or similar having a bar with a bar diameter. The device can have an annular or disc-shaped body. The annular body can have an inner disc perimeter defining a central aperture having a diameter substantially similar to the bar diameter of the host apparatus. The annular body can also have a slot extending through the annular body from an outer perimeter to the central aperture defining a first disc end and a second disc end separated by a slot width. The annular body can be formed of a material having an elasticity sufficient to allow axial flexibility that returns the annular body to its original shape after being deformed to fit around the bar of the host apparatus.