This bundle includes one 6-pin, two 8-pin and one 10-pin single row headers with 15mm long leads that make it perfect for use with Arduino Uno R3 Shields, and they're stackable. This header bundle is intended for the Uno R3 layout. We also carry the standard stackable header bundle (P/N: 2137756) that includes two 6-position and two 8-position headers for older Arduino shields. They are also available separately, see below.