Slide it to the side to release the tension from the spring loaded bar and remove the strap at an angle. To reinstall, put the side without a prong first, then squeeze the prong, slide the strap in place and release the prong – you may have to gently move it around until the springbar mechanism finds the hole and pops in.
What are the advantage of quick-release springbars?
The first advantage of quick-release springbars is in the name: quick. No tools needed, making it an ideal system for watch enthusiasts who like to change their watch strap often. Another advantage is that quick-release springbars tend to be built into the strap design. This means you won’t have bars flying around the room.