While the look may reference the steel wheel of yesteryear, the STL is a one-piece aluminum design that utilizes the latest in low-pressure casting technology.. Rotiform Wheels STL, 20x9 with 5 on 120 Bolt Pattern - Gloss Black - R19120902161 The results are a rugged low-weight wheel finished with Rotiform's signature high-quality finishes and attention to detail. Rotiform is known for trendsetting design and the STL is no exception.