Bushnell does not currently offer caps for this optic and there is not enough mounting space for aftermarket caps.
I use a small sock
I bought covers to protect the Bushnell TRS-26 red dot on Ali Express. For the front, I bought a 35mm cap, and for the back - a 37mm cap. Of course, the rear part, due to the special shape of the red dot, has a small gap between the optics and the cover. They cost about $4 each including shipping. Delivery takes a very long time (3-6 weeks).
The OpticsPlanet does not allow links, so try searching Ali Express for the name - "30mm-69mm Flip Up Quick Spring Cap Objective Lense Lid Hunting Rifle Scope Caliber Scope Lens Protection Hunting Gun Accessories".
trijicon sells a pull off fabric cover that goes over the entire red dot, it is designed for the MRO it is not a perfect fit but does work
I bought covers to protect the Bushnell TRS-26 red dot on Aliexpress (seller - Tactical Corps Store). For the front, I bought a 35mm cap, and for the back - a 37mm cap. Of course, the rear part, due to the special shape of the red dot, has a small gap between the optics and the cover. They cost about $4 each including shipping. Delivery takes a very long time (3-6 weeks).