Bait casting reels are reels in which line is stored on a revolving spool. The bait casting reel is mounted above the rod, hence its other name, the overhead reel. The bait casting reel dates from at least the mid-1600s, but came into wide use by amateur anglers during the 1870s. Early bait casting reels were often constructed with brass or iron gears, with casings and spools made of brass, German silver, or hard rubber. Early reels were often operated by inverting the reel in order to retrieve line by back-winding, and the reel crank handle was positioned on the right side of the reel for this reason.As a result, the right-hand crank position for bait casting reels has become customary over the years, though models with left-hand retrieve are now gaining in popularity. Many of today's bait casting reels are constructed using aluminium, stainless steel, and/or synthetic composite materials, and include a level-wind mechanism to prevent the line from being trapped under itself on the spool during rewind, thus interfering with subsequent casts. Many are also fitted with anti-reverse handles and drags designed to slow runs by large and powerful gamefish. Because the momentum of the forward cast must rotate the spool as well as propel the lure, bait casting designs normally require heavier lures for proper operation than with other types of reels. ************************************************** Spool tension on most newer bait casting reels can be adjusted by means of adjustable spool tension, a centrifugal brake, or a magnetic 'cast control' to reduce spool overrun during a cast and resultant line snare, known as backlash. Each time a lure of a different weight is attached, the cast control must be adjusted. The bait casting reel design will operate acceptably with a wide variety of fishing lines, ranging from braided multifilament and heat-fused 'superlines' to copolymer, fluorocarbon, and nylon monofilaments. Most bait casting reels can also easily be palmed or thumbed to increase the drag, set the hook, or to accurately halt the lure at a given point in the cast. A variation of the bait casting reel is the big game reel. These are very large and robust fishing reels, designed and built for heavy saltwater species such as tuna, marlin, sailfish, and sharks. Big game reels are not designed for casting, but used for trolling or fishing set baits and lures on the open ocean. Bait casting reels are sometimes referred to as conventional reels in the U.S. They are known as multiplier reels in Europe, on account of their geared line retrieve, one turn of the handle resulting in multiple turns of the spool.