Screw clamp mechanisms usually only work optimally with anti-slip underlay material. If you use an aero handlebar attachment such as the BHB-52, you should make sure that it´s mounted unshakeable tight - for your own safety.
The BHB-52 Shims Set includes 2 pairs of shims for the top and bottom of the screw clamp and a pair of replacement screws for the clamp itself. So if the wear has struck on you, this set provides relief.
Racer, Aero, Endurance
Shims for screw terminals
BHB-52 AeroBase handlebar attachment for 25.4 / 31.8 mm handlebars