A Curb mount sits off of the roof with a wooden frame and
metal flashings around the wooden base. Highly recommended it’s durable and
water tight.
A self flash skylight has only a little plastic edge around
it, with a self flash you are inadvertently relying on caulking or silicone to
keep the water out for many years to come. They are excellent traps for water
and are very hard and expensive to repair.