(Pocket-lint) - A lot is happening in the world of Jawbone, specifically with its fitness trackers. Although we will still have to wait until later this year for the sensor-laden Up3 to hit the UK (US shipping starts 20 April), there are also two new devices coming.

Again, the Up2 and Up4 devices are scheduled for the US initially, but could make their way to these shores too in future.

The Jawbone Up4 is the more unique and high-end of the two fitness bands. As well as provide fitness tracking like many of the company's products, it also has NFC on board for contactless payment duties.

Jawbone has partnered with American Express in the States to include the ability to pay for goods in stores that accept contactless payment. Through the Up app for iOS and Android, you connect an eligible American Express card and can then tap to pay for items.

The Up4 also features the same sensors as the Up3, including the heart rate monitor, and will cost $199.99 (£135) on its American release in the summer.

READ: Jawbone Up3 with HR monitor, plus budget Up Move model unveiled

The Jawbone Up2 is a more conventional tracker, featuring the same design aethestics as the Up3 but without the heart rate sensor and is therefore positioned at a cheaper price point. It will set you back $99 in the States and, like the Up3, will be available very soon. It can be ordered from Jawbone.com, BestBuy.com or Amazon.com now and will be in Best Buy stores in the US from 19 April.

Writing by Rik Henderson.