Many fatbikes with wider BB shells can utilized similar BB cups within the same standard as their narrower shelled MTB versions. One exception to this is the e*thirteen PF30 Fatbike BB (part number BB20.P-PF30PRS.K). 

Our MTB shell width PF30 bottom bracket (part number BB20.P-PF30.K) actually has sleeves which thread together inside the BB shell. However, the fatbike version of this BB utilizes 2 press in style cups which do not thread together. 

The FATBIKE PF30 cups are shown here:

The MTB shell width PF30 bottom bracket (part number BB20.P-PF30.K) is not compatible with fatbike applications due to a reduced press fit and shorter skirt length. 

The Fatbike PF30 BB is no longer in production as e*thirteen has stopped producing fatbike cranks in 2017/2018. There are some non e*thirteen options still on the market which may be compatible with e*thirteen cranks, these include offerings from Race Face (vendor part #: BB4610030B13 / UPC: 821973272900). Alternatively, a PF30 --> BSA adaptor cup could be used in the frame and then then an e*thirteen BSA threaded BB installed.