The Smooth Operator is a "slammed deck design". Meaning is has a low overall height to the main frame plates. However, even though there may not look like much room you can actually fit a surprisingly large range of electronics in the frame. The ESC and FC sit next to each other, not on top of each other like in other frame designs. 

Flight Controller: 

Nearly any standard sized (36mm x 36mm form factor - 30.5mm x 30.5mm mounting) FC will fit. Due to the slammed design its best to use a FC with a low overall height. Tall components on top or bottom of the FC may make for a slightly more cramped FC bay so be mindful of this. Since the FC and ESC fit next to each other you will need to run a wire pigtail from the FC to the ESC. You cannot pin them together. Most all-in-one speed controllers and FC's these days come with the option to run a wire pigtail. Another option is an FC with built in PDB for use with single ESC's mounted to the arms. 

Electronic Speed Controller: 

Nearly any standard sized (30.5mm x 30.5mm mounting) all-in-one ESC will fit. The frame is designed primarily for all-in-one ESC's but you can run singles on the arms if you prefer. The arms are 9mm side so keep this in mind when choosing an ESC. If you decide to use single ESC's you must select an FC which has a built in PDB. 

FPV Camera: 

To our knowledge ANY micro sized camera on the market will fit this frame. For example: Runcam Eagle, Runcam Micro Swift 2 / 3, Foxeer Monster, Foxeer Predator, Runcam Sparrow 2 / 3, or similar. This frame WILL NOT fit mini cameras or standard sized "HS1177" cameras. 

FPV Video Transmitter: 

This frame design places the VTX below the FC. This "VTX Bay" as its called, has a standard depth of around 9mm max for flat bottom FC's or less depending on the components on your FC board. With THIS optional accessory you can increase the VTX bay height by 2.5mm allowing for a taller VTX or additional items, like a buzzer or capacitor. The ideal VTX is a Unify Pro HV race, Unify Pro V3, Unify Pro HV, Unify Pro Race MMCX. It is best to choose a VTX that has a low overall height. However, other brands will fit. To see the VTX Bay opening size hit THIS LINK. 

Receiver:

The frame is designed to place the receiver under the ESC. Receiver bay depth is around 8mm depending on the ESC you use. You can increase the bay depth by 2.5mm with THIS optional accessory. Receiver bay opening dims can be located HERE. 

Motor: 

Any motor with either 16mm x 16mm mounting pattern or 16mm x 19mm mounting pattern will fit.