lm7 resin is composed of the lm7 ligand cross-linked to agarose resin.
TriAltus offers Im7 coupled to both 6B and 4B agarose beads. The choice between 4B versus 6B resin will depend on binding capacity and flow rate. Because the 4B resin has a larger pore size, its capacity is increased, but it is more susceptible to compression. Therefore, 4B resin has a lower maximum flow rate. 4B resin may be helpful for purifying larger proteins because of the increased capacity and increased residence time, but we do see increased backpressure from our 1 mL 4B FPLC columns.
If your experiment requires a higher flow rate, then 6B may be the better option. 4B and 6B resins both yield the same high purity and activity of target proteins, and other elements of the protocol (e.g., buffers and regeneration procedures) are the same.