The Apple Vision Pro just got a little more expensive, thanks to a new line of accessories.

On Friday, Apple started selling add-ons for its new mixed-reality headset, which already starts at $3,500. Pre-orders for the Vision Pro began the same day, with delivery already backed up at least into March. The device is set to launch in the US on February 2.

Some of the available accessories include a $199 travel case, $199 battery, and $49.95 Belkin battery holder.

Apple is also selling two kinds of gray headbands for the device – a solo knit band and a dual loop band – for $99 each.

Alone, the $3,500 Vision Pro comes with 256 gigabytes of storage, both bands, a light seal and two cushions, a cover for the front of the device, a USB-C charging cable and power adapter, and Apple's $19 polishing cloth.

Users who ordinarily wear prescription or reader glasses can get optical inserts for $99.

An extra light seal, which blocks out light and helps the Vision Pro better fit your face, goes for $199. The light seal cushion, which is primarily for comfort and attaches magnetically, is selling for $29.

Add these up, and the cost for the Vision Pro and some accessories could easily exceed $4,000.

Apple is offering free demos at US Apple stores next month. Signups open February 2 at 8 a.m., with demos available that weekend on a first-come, first-served basis.

In the live 25-minute Vision Pro test runs, employees will demonstrate how to use the headset instead of a laptop or iPad. Users will also watch 3D and immersive films, including one that simulates the viewer being on a tightrope, according to Bloomberg.