The "3 TLE" (German "Teile", parts) says it is a 3-part message; the "1TL" (German "Teil", part) says this is the first part; the "172" says there are 172 characters in the message (including the message key). For this message, the ground setting "FRX" is transmitted twice in the clear; the ground setting would/should be different for every message on net. Consequently, the Poles could not find the needed sixty message keys encrypted under the same ground setting. Without the same-key message volume, they could not determine the characteristic, so they could not determine the permutations "A B C D E F" or use the grill. For this message, the daily settings (rotor order, plugboard, and ring settings) were used with "FRX" to decrypt the first six characters ("HCALN U") to obtain the doubled message key ("AGIAGI").