San Francisco, Jan 2 : Samsung has opened pre-order reserve bookings for its upcoming Galaxy S21 lineup of phones in the US and people can book a slot when the devices become available, which is usually after the likely launch event ends on January 14. Those who pre-book can get up to $700 of instant trade-in credit toward the purchase of a Galaxy S21 "if you trade an iPhone 12 series phone, or one of Samsung's own Note 20 and S20 phones". The company is also offering up to $550 of trade-in credit for certain phones with cracked screens. "Be the first to know about the next Galaxy. Reserve to unlock an extra $50 instant credit for accessories. Plus, get an extra $10 in the Android Shop Samsung App," Samsung said on its US website. The company is asking for some basic information like your name, email address, and zip code. You do not need to pay anything to reserve your preorder. Samsung is expected to launch three models of the S21 Series -- Galaxy S21 5G, S21+ 5G, S21 Ultra 5G. The S21 would have a 6.2-inch display, the Plus would be 6.7 inches and the Ultra would reportedly have a 6.8-inch display. The Samsung Galaxy S21 Ultra shows its camera module supposed to feature a 10MP 10X super-telephoto zoom, a 108MP main, a 12MP ultrawide and a 10MP 3X telephoto camera. Galaxy S21 Ultra might feature a laser autofocus system that would replace the Time-of-Flight (ToF) sensor found in its predecessor. The Galaxy S21 would come in phantom violet, phantom grey, phantom white and phantom pink colours. /IANS