Apple (AAPL -0.81%) is likely just months away from taking the wraps off of its expected iWatch. The Mac maker could easily sell tens of millions of units of its smartwatch, which represents a significant opportunity for any component suppliers lucky enough to win a spot. Looking at recent Apple devices, investors can speculate on companies that Apple may tap as vendors. Possible names include NXP Semiconductor (NXPI +0.70%), Universal Display (OLED +0.45%), STMicroelectronics (STM +0.26%), and OMRON Global.