Neveu–Schwarz–Neveu–Schwarz sector ($8_v\otimes 8_v=35_v\oplus 28\oplus 1$)

The closed-string sector with NS sector excitations on both chiral sides. Its massless transverse tensor product is $8_v\otimes 8_v=35_v+28+1$, giving the graviton, Kalb–Ramond field and dilaton. These fields are common to the type II theories.

The antisymmetric two-form gauge potential couples electrically to a fundamental string. Its field strength is locally $H_3=d{B}_2$; its magnetic source is an NS5-brane.