BsmBI-v2 is a Type IIS restriction enzyme that requires incubation at 55°C and is supplied with  NEBuffer r3.1. Esp3i is an isoschizomer of BsmBI-v2 that requires incubation at 37°C and is supplied with rCutSmart Buffer™ (>210 restriction enzymes are supplied with rCutSmart). Both these enzymes are used in Golden Gate Assembly.