m7GpppAmpG ammonium is a trinucleotide 5′ cap analog with the capping efficiencies for the obtained RNAs of 90%.
References:
[1]. Sikorski PJ, Warminski M, Kubacka D, et al. The identity and methylation status of the first transcribed nucleotide in eukaryotic mRNA 5' cap modulates protein expression in living cells. Nucleic Acids Res. 2020;48(4):1607-1626.