Sports Performance eXtreme, or SPX, is a footwear and sports apparel brand, which was popular back in the late 1980s and early 1990s.
The company logo was one of the most noticeable at the time, with a smaller SP sitting in front of a large red X, with a crown sitting above.
There were three designs that formed the main cornerstone of the brand in the late 80s, and they were all based around the popular basketball style trainer :-
Street Slam - An over ankle high length boot. Street Lo - Low version, below ankle.
Street Diss - Over Ankle high. Diss Lo - Lower version.
Freestyle - High ankle version - probably the most common and popular at the time.
These trainers played an important part of the whole 'Basketball trainers' scene, along with Troop, British Knights, LA Gear amongst others.
In 2002, the brand was relaunched under the same name.