Dual Blinds are exactly that two blinds fitted using the new slim bracket on your window
Block out Blinds are use where little or no light transfer is required, they also offer good heat retention inside the home and sun exclusion from outside.
Sunscreen Blinds offer the benefits of allowing good vision to the outside during the day and restricted vision in. They are great to provide shade in the summer and reduce glare. commonly used in conjunction with a block out blind fitted "DUAL" a economical way to full cover your windows.
Generally the Block out is fitted on the front "room side" and the Screen to the back.