I've put up a video of an SMB deployment here - another skills which is formally taught on the fundamentals class.

In many diving scenarios, surface markers can be used to communicate with the surface either as part of planned marking of ascending divers, or in the event of an emergency. A dive team must be able to deploy any one of several inflatable surface markers with ease.  

Proper trim and buoyancy is an essential part of any dive. It becomes critical during the final phase of the dive, facilitating effortless ascent procedures and effective decompression. 

From GUE.com - Director of Training. 

Managing an unconscious diver while under water is a problematic scenario. It is clear that a range of nuances create some doubt about the perfect management. Furthermore, different scenarios likely result in additional complexity; it is impossible to craft a strategy that operates independently of these variables. Yet, it is nearly impossible to revive an unconscious diver while at depth, making it likely that an efficient ascent is the most successful strategy. Very calm and proficient rescuers may be able to manage multiple aspects of a rescue without compromising an efficient ascent.

Yet, most rescuers should focus on a few important points, ensuring they do not sacrifice safety or efficiency. We would argue that three areas should be the rescuers primary focus; these include maintaining control, keeping an open airway and ensuring a smooth ascent. Failure to properly manage any of these areas is likely to result in a failed rescue. 

Seeing a Tech 1 diver swimming backwards was the most amazing site I’d seen as a new diver, I’d done about 30 dives at that point and was fascinated.  I really wanted to learn how to do this. 

I've heard it described as the DIR advertising gimmick - and had divers say that they have no more need to swim backwards than learn to wriggle their ears. 

It’s not just a party trick though – being able to kick backwards is vital for holding your position in the water whilst keeping an eye on the people you are diving with.

I’m not going to try to explain the exact technique on the internet – best that you are taught directly.  But for those of you who have been shown the elements of a back kick, yet struggle to make it reliable and effective, I’ll set out a few tips and reminders to help you improve.

It would be possible to write whole books on the various problems that people have with valve drills, and the convoluted solutions that some come up with to address their problems.  

Firstly, forget moving the bands on your tanks. Put them at the break of the neck and leave them there. The problem with moving bands is that you cannot simply use sets which are not ‘set up’ for you. Travelling, borrowing tanks from others if yours are in for test or full of gas which is inappropriate for your dive, all are problematic if you rely on band position which is different to the standard – so don’t  be tempted to fiddle!

If you are diving a one piece harness it can be positioned to place the tanks anywhere on your back that you require – there is simply no need to move bands if your harness is set up correctly.