Apple’s first wearable becomes available for pre-order on April 10. That same day, prospective buyers can also head to their local Apple retail store to try the device on, test out various bands and determine which size watch face is the best fit.

Demand is still a big question mark but it’s entirely possible that the first batch of Apple Watches sell out online long before Apple opens its doors for business that morning. What’s more, most people have a job to attend that Friday while others may not live within a reasonable distance from a retail store.

How is one expected to pre-order Apple Watch with any degree of confidence, sight unseen? Don’t worry, Apple has thought of that.

The company has updated its Apple Store app with listings for its new wearable. Here, interested parties will find a guide that outlines band size based on wrist circumference (that information is also available online in PDF format by clicking here).

With options for wrists measuring 125mm to 215mm around, most are likely to find one that fits securely.

The bigger question for many will be trying to determine which size watch face to purchase. For this, Apple has added actual size images of both the 38mm and 42mm watch face to its Apple Store app. By placing an iDevice near your wrist, you can get a pretty good idea of just how big each version is.

Apple Watch ships on April 24 with prices starting at $349 and topping out at $17,000.