This bit is hand forged in burnished steel.
It has two jointed twisted mouthpieces. Each joint is off-centre, the theory is that this rather severe bit puts pressure on the bars of the horse's mouth.
One mouthpiece is stamped "J.H." with abroad arrow - possibly an ordnance mark indicating military use.
"J.H." stands for John Hawkins who, according to the Saddlery & Harness Journal, was apprenticed to the bit making trade aged nine and set up his own company in 1840, he died in 1891, leaving the company in the hands of his sons James & Benjamin.
I have yet to identify the bit rings - they appear to be somewhere between D-rings and eggbutts,
Dimensions : Mouthpiece 5½" (14cm), Cheek ring diameter 2¾" (7cm)
Weight 276g (9¾oz)
Ref : bit422