The 4 Ring has 2 rings on the bottom to adjust the amount of poll pressure and leverage you want.
The Barrie Reversible is a severe bit due to the center links of the two pieces being offset by 20mm giving it a double nutcracker action, which creates more tongue and bar pressure.
All our bits are made from blue sweet iron, because it:
helps bit acceptance
is warm and sweet
Please note the blue will fade with use.