The NH21M13LC from Nihon Dempa Kogyo is a OCXO with Frequency 12.8 to 20 MHz, Supply Voltage 3.3 V, Output_Voltage 0.4 to 2.4 V, Load Capacitance 15 pF, Frequency Stability ±5 to 500 ppb. Tags: Surface Mount. More details for NH21M13LC can be seen below.