IF you're a Sky customer you've probably noticed quite a few mysterious codes listed next to your favourite shows.
The meaning behind some are more obvious than others.
But all are handy to get the best out of your telly.
There are seven that appear on Sky and here is what they mean.
AD
AD means Audio Description.
Sky customers can get £100s of rewards with little known trick
This provides an enhanced audio experience with extra commentary for blind or partially sighted people.
DS
DS stands for Dolby Surround.
Programmes and movies with DS offer surround sound if you have a compatible TV or speaker system.
HD
HD is one you probably already know - High Definition.
Perhaps obviously, this code not only means it's in HD but also in widescreen.
S
The S code stands for Subtitles.
Subs will appear when switched on for these shows.
SL
SL means Sign Language.
Signed shows are special versions of the programme you want to watch with, so the signer can't be turned on or off.
Sky is giving out set-top box upgrades for free - are you eligible?
UHD
Another pretty obvious one is UHD, for Ultra High Definition.
Don't forget the HD channel you're watching may have a UHD version for a better telly experience.
W
W means Widescreen.
It won't appear if you're watching a show in HD though, as HD shows are all in widescreen anyway.
We pay for your stories! Do you have a story for The Sun Online Tech & Science team? Email us at tech@the-sun.co.uk