White ring with a black alpha-numeric code (on left leg) and c-ring above metal ring (on right leg).
note 1 : c-ring on right leg = project marker (white, yellow, red, orange, blue).
note 2 : used letters are A, B, C, E, F, G, H, J, K, L, M, N, P, R, S, T, U, V, W, Y, X and Z.
note 3 : used numbers are 0 - 9.
note 4 :