Hi,
The SL line of binoculars is optically similar to the traditional Habicht porro product line.
They are rubber-coated, introduced today's swaro ergonomics (large thumbs relief). They have a front-located focus wheel, a very heavy-duty hinge.
As Otto mentioned, they are waterproof and can be dropped without suffering much damage.
If you intend buying one, be sure to check for wear in the focusing mechanism (eyepiece must move back and forth while focusing - if not mechanism is broken). Besides, the prism coatings have a tendency to peel ; have a reverse look through the objectives to check for optical cleanliness.
I have a 7x50 item and had a 10x50, both very nice for star-gazing ; test-benched a few others, too. the view is perfect, except for a little geometric aberration. The 7x items have a very narrow field.
Best regards,
zp.