Update:  Valve has come forward to confirm the information detailed below. “The tech info on that page, while not comprehensive, is accurate,” Valve spokesman Doug Lombardi told The Verge.  

Valve reportedly plans to announce the headset on May 1st, with preorders starting that day. Lombardi also said that the June 15th ship date may move, but the company is targeting sometime in June.

It looks as though the Valve Index headset teased over the weekend will ship on June 15th alongside two unrevealed controllers. 

It's worth noting that Valve has yet to officially confirm the June 15th ship date, headset or controllers yet, but based on a teaser image, more information can be expected in May. 

Based on screenshots grabbed by Wario64 on Twitter, the Valve Index will ship with the headset, integrated headphones, power adapter, regionalized power adapter plugs, 2 face gaskets (narrow and wide), and a cleaning cloth. 

The Valve Index controllers, on the other hand, are shrouded in mystery in terms of its design. A blank screenshot accompanies the currently bare Steam page for the product, aside from some hardware specifications.