Dorr camera lens cap cover
Three certainties in life: death, taxes and lost lens caps.
Joking aside these are the good pinch-style lens cap covers and they come with an elastic lanyard that wraps around your lens if you so wish, to prevent any future losses and sadness.
Pro tip: have a look at the front of your camera lens. You should see something like this “⌀58mm” that means you need a 58mm lens cap.