"$5,800 for V6.5 ES cells (C57BL6 x 129 Sv), R1 ES cells (129 Sv x 129 SvJ) and TL1 ES cells (129 SvEvTac) or $6,800 for C57B/6 ES cells. We usually pick 192 clones for further screening (from two 96 well plates). Germline transmission is guaranteed for the V6.5 ES line as long as the targeted allele does not cause embryonic lethality. We will not charge additional fees to obtain germline transmission if it cannot be obtained after injection of at least three independent clones. All the above cell lines have been extensively tested for germline transmission: For the V6.5 C57BL6 x 129 Sv hybrid line > 80% of injected ES clones go germline. In addition, PGT has developed improved growth conditions for C57BL6 ES cells. PGT routinely achieves rates of germline transmission for this desirable but technically challenging mouse background that are comparable to the rates for some 129 ES cells (about 55 % for a single C57BL6 ES clone)."