Razer's New Basilisk FPS Mouse has a Thumb Clutch

Razer Basilisk Mouse (Razer)

Razer's new FPS mouse that it calls the "Razer Basilisk Mouse is primarily aimed at those that prefer mouses with a thumb-grip and on the side it has a thumb clutch that you can use for either holding your breath while sniping or adjusting your mouse dpi on-the-fly to slow down in order in order to get that precise aim on your targets. You could also attach the rubber cap if you prefer not to use the clutch and it has 2 more lengths for the clutch so that it can fit multiple hand sizes . 

Razer Switchable Thumb Clutches (Razer)

It also has an adjustable scroll-wheel which is good for which would be useful for switching weapons really fast in the middle of tense firefights when you run out of ammo with your primary weapon.The Razer Basilisk Mouse is rated at 16,000 dpi but most people including myself would leave it at a lower speed like 3,500. The internal sensor is the same as the deathadder elite. The mouse features mechanical switches on-board and it's rated for 50 million clicks according to Razer's charts

Based on my experiences and I say this as a bit of honesty. I would wait for reviews with any Razer product, My deathadder 3.5 still works perfectly but I wouldn't go with any wireless razer mouse because they are buggy and when the battery gets low the mouse pointer gets figity, There's no warning for when the battery gets low in-game or on the desktop. It's best to go with wired mouses anyway if you game a lot or spend a lot of time on the computer so other than that bit of criticism my experience with Razer mouses have been decent overall.

Those whom would like to buy one can do so at Razer's store or they could grab it at Amazon if they prefer to play it safe with Amazon's 30 day return and you can grab an extendable warranty for extra costs if you would like there.

Source: Razer