The Overland runs on pneumatic tyres, and pneumatic tyres need topping up. This is the pump made for them, so your client or their support worker can keep the pressure where it should be without hunting for a bike pump that fits.
Tyre pressure matters more on a walker than people expect. Soft tyres roll heavily, drag on grass and gravel and make the brakes feel vague, which is exactly the terrain the Overland is bought for. A quick check every few weeks keeps the walker rolling the way it did on delivery.
It is small enough to live in the walker bag.
