Now I own two Sleipnirs, one in large (this one) and one in XL, for most people I’m going to recommend they get the large size, both of these dildos are large and very blunt so you’re going to want a lot of practice before moving to the XL size.
I equate both sizes to shoving a log up your ***… (lol) they are really thick the whole way down and have a very blunt head. The large Sleipnir is about the same diameter as a soda can , while the XL is about an inch wider. When I say “they are really thick the whole way down”, I mean it. From the BD website, Large Sleipnir starts at 3.1 inches and has a 3.2 inch (diameter) shaft. He’s a log!
Both of my Sleipnirs are soft shaft firmness, while my XL has a firm base. Given how blunt the toy is and how thick it is, I would recommend soft firmness in both cases. My Large Sleipnir will stand on its own but the XL will not (mine has a suction cup though so maybe it would if it didn’t have a suction cup). 

Specs (From Bad Dragon):

• Circumference (head): 9.5 inches
• Max Circumference: 10 inches
• Total Length: 12 inches
• Usable Length: 10 inches
• MSRP (as owned): $145.00

Check it out here!