You probably call them "suspenders" - those elastic straps which go over your shoulders and attach to your pants in order to keep them up.  The British call them "braces", a term I like.  Braces are far more forgiving than belts.  When you need an extra bit of room in your knees or legs, the braces will stretch.  When you dismount or stand, they pull your breeches back to the correct position.

These New Jersey police breeches, on loan to me from a friend in Minnesota, came with the correct bottons attached.  The braces are from David Morgan, a company in the Seattle area.  The boots are 20-inch riding boots and have no labels.

Here is a rear view of the same outfit.  Note the "Y" formation and the thin leather straps which attach to the buttons on the INSIDE of the waistband.  Also, note the double seat, sometimes referred to as an "arse patch".

Braces are great if you wear heavy weight breeches.  These German police leathers are designed for long hours in the saddle.  They have a flannel lining, double knees and seat, and a combination button and zipper fly.  They are HEAVY!  I love 'em in rough weather!

Note the full cut of these leather breeches.  It is interesting that there are NO belt loops.  Braces must be used, and they attach in back to leather straps which come up from the waist band.  This seems to be a German tailoring style.  The boots are my 18-inch leather lined Wescos.  You all ready to hit the road?