The FX regulator has 5 o-rings in total. Two of the same size outside of the body and three different o-rings on the inside. OUTSIDE: - nr. 17047 x 2 (11,91x2,62 Nbr 70) INSIDE: - nr. 15015 (6,07x1,78 Nbr 70) - nr. 15016 (2,9x1,78 Nbr 70) - nr. 19225 (7,5x2,0 Nbr 70)