Fmoc-Ebes-OH (N-(Fmoc-8-amino-3,6-dioxa-octyl)succinamic acid) is a PEG-like linker developed by Song, et al. for use as a building block in SPPS. It is linear, flexible, and hydrophilic. The enhanced solubility and ionization ability make it more amenable for mass spectrometry analysis. This Fmoc protected spacer is available in crystalline form and can be stored at 4°C for two years without significant decomposition.