Double-jointed bits will follow the shape of the tongue better than a single jointed. They eliminate palate interference and breaks to the outside of the tongue. At Fager, you will only find short centerpieces where the joints are not laying on top of the sensitive bars. 

Max Titanium Fixed rings
65 EUR 129 EUR
Max Titanium Loose rings
65 EUR 129 EUR
Julia Sweet iron Wings
50 EUR 99 EUR