Elon Musk is determined to make recreational space travel a thing. He is also involved in resupply missions, with plans of expanding those efforts. If you are wondering what an astronaut would look like when all geared up for travel above the earth's atmosphere on a SpaceX flight, Musk answered that question by posting a picture to Instagram of a fully functioning suit. Or put another way, what you see is not a mockup, it is the real thing and it really works for space travel.
According to Musk, the suit is capable of withstanding twice the pressure of the vacuum of space, based on testing that has been done. He also notes in his Instagram post that getting the right balance of form and function was challenging. Based on a single photo of the suit, we have to say that Musk and his team ultimately a did a good job in the style department, and assuming it works as advertised, in the function department too.
The SpaceX suit is meant to be worn by astronauts hitching a ride inside the company's Dragon capsule in the event it depressurizes. At present, the crewless Dragon capsule is used to bring supplies to the International Space Station (ISS). Sometime down the line, NASA astronauts will wear the suits as part of its commercial crew program that will transport humans to the ISS.
Boeing is another company that is planning manned space missions. However, Boeing decided to outsource spacesuit production to David Clark Company, whereas SpaceX sought to keep costs lower by keeping much of the design and manufacturing in-house.
Given what looks to be a comparatively lightweight design versus NASA's bulky spacesuits, this is likely only to be used for space travel and not for spacewalks. Musk promised more details soon.