There are at least 3 variants of Atari ST (whether SF354 single-sided or SF314 double-sided) drives.
....has pictures of them all.
NOW - I HAVE AVOIDED THE "SLANTY" DRIVE - that's the one with the obviously-slanted disk slot and eject button. Back in 1986-1988, we all recongnized this was a drive mech my Chinon (we used to call it SHIT-ON) where the read/write head was allegedly fastened to the hardware with a spot of glue that would eventually release. Leave it to Tramiel's Atari Corp. to continually seek lower bids, sacrificing quality all the way.
So, the FIRST Atari ST drive mechs (posted in the above-referenced post in the order of occurrence - Atari SF354, Atari SF314) were 1/2-height (but so huge in retrospect that you *want* to call them "full-height" - but the term is still relative to "full-height" mechs like the 5 1/4 in the Atari 810, so it really was "half-height." These original SF354 and SF314 drives had *really* noisy drive mechs, that actually "growled" while they ran. Big and old as they are, it has been my experience that they are nearly bulletproof; quality was built-in to the over-engineering that I have several examples in my possession to this day that function flawlessly, and I haven't encountered one that does not, but that individual experience may not be representative. NOW, these original drives utilize the STANDARD 34-PIN CONNECTOR. This makes it great to swap in an HxC Floppy Drive emulator, etc., but I realize that's of zero concern to fixing and unloading an 8-bit drive, so I digress.
The SECOND was the "slanty". I did - at one time - have a 1040ST (about 1989) with this drive, but I've never owned an external, and I moved to IBM PC before I experienced a failure, but I do understand it to be unreliable.
The THIRD was the EPSON mech (note: AT THIS TIME 1/3-HEIGHT like modern 1.44 drive), and I do beleive that this MOVED BACK TO the standard 34-pin (dual-row) connector, as I now have *several* machines with this drive. This is the 3rd one displayed in the above-quoted post.
As an ST (and A8, and whatever-else) user, I have specifically-avoided the drive mech that I think you seek. However, even NOS Atari SF354s (nobody wanted that shit in the ST world because it was single-sided, anyway) are rife on Ebay, and you just need to look for the "slanty" one, but THIS IS ASSUMING THAT ALL SLANTY ONES USE THE NON-STANDARD SINGLE-ROW CONNECTOR. I can tell you from personal experience that I have replaced both (1) the original "growly" behemoth with an HxC floppy emulator, and the 3rd "1/3-height" with an HxC floppy emulator. Had I owned a non-standard single-row machine (ST computer with internal drive) or drive (external drive), then I would have not been able to utilize the HxC.
You need to seek out the SF354 with the slanty drive, obviously, and this should be cheap. Now, the outlying question (as I have almost no experience with that drive) is WHETHER OR NOT ALL *SLANTY* SF354/SF314 USE THE SINGLE-ROW CONNECTOR. It is also worth noting that the "slanty/single-row-connector" SF354/314 also changed the power supply; they dropped one of the voltages (think it was 12V?) and reversed the gender of the connector to prevent the earlier power supply from being plugged into the new shit drives.... Someone more knowledgeable, please chime in and correct and add-to this....
edit: earlier, I said "polarity" of the connector, but I meant "gender."