The Seiko monster range of watches is another iconic variation of the beater tool daily user, ISO6425 certified diving watch. A fabulous and totally unique design which has a presence on anyone's wrist comparable to a lot more expensive watches. The 200m monster range, at the time of writing can be divided into 3 generations to try to make sense of a somewhat confusing array of watches! This is basically defined by the movement used, although all of the movements are based on the base 7s26 movement going forward. For the purpose of this we will not be adding the K or J or 1 or 2 etc at the end, please look up Seiko under the brands section for clarification of this. The 1st generation monsters, with the model numbers SKX779, black dial, SKX781, orange dial, are the most popular, and came with the same case and legendary 7s26 movement, but there were some unusual limited edition models, SKZ213, blue dial, SKX243, red dial, SKZ203, yellow dial, SZEN001, all black, orange dial, SNEN002, all black, black dial, SZEN006, all black, white dial, SZEN007, all black, dark red dial, and there are probably a few more! Mainly sold in the Asian market, and JDM ( Japanese domestic market) some of the limited editions had the very similar 7s36 movement. The supply of these 1st generation monsters is now drying up, and now sometimes referred to as classic monsters! They are being replaced by the 2nd generation of monsters , now called the superior by Seiko, which is a little confusing! Followed by some models as prospex, even more confusing!! Basically the case is the same as the 1st generation, but now has a knurled finish to the winding crown, so easily recognisable! The biggest change is in the movement, which has now been upgraded to Seiko's 4r36 movement, the difference being that this movement enables hand winding and has a hacking second hand when adjusting the time, the model numbers in this range are, SRP307, black dial, SRP309, orange dial, SRP 311, all black, sunburst dial, SRP313, black dial with red surrounded markers and hands, SRP315, orange & black dial, black bezel. Then under the Prospex logo the SRP581, all black, blue bezel, and the SRP583, all black, gold crown, and there again there are probably a few more variations available! The third generation monsters, with the model numbers SBDC023, and SBDC025 (and probably a few more!) Have the 6r15 movement, a more upgraded movement that has a 50hr power reserve thanks to the Spron 510 mainspring, recognisable by the lack of day date, now date only! In addition to all of these are the night monsters and the trek monsters variations and there again probably more! No matter what model your personal preference is, these are all great watches and highly recommended by us, as are all the Seiko automatic diver's range of watches!