The 893024 antenna
belongs to the RX-xx-DR-M-LINK receivers as shown here:
The 1-00421 antenna
is suitable for almost all the other receivers M-LINK-receivers, especially the DR-receivers. Alas there might be different lengths. For example the RX-DR-compact receivers have two antennas with different length. So to be sure to get the right length you may contact the MULTIPLEX service.
For all 2,4 GHz receivers (M-LINK or others (Fasst, HOTT, Jeti ...)) the rule applies: the effective antenna lenght is 30 mm and in most cases it is the bare end of the arial . Some arial have a cover shrunk over these ends (sometimes in different colors). You must be careful with shrinking a cover over these endings yourself: black shrinking tube might include carbon particles which reduce the antenna efficency. The matter has already been discussed here in the forum!