What's the stage like?
Not quite as hard as Stage 16, as the first half is mostly downhill, but nonetheless it's 165km with two, category one climbs in the last 40km.
They are tough climbs, too, especially the Salita del Menador that provides the nearly-but-not-quite summit-finish: 8km at an average gradient of 10%, with sections towards the top of the climb of around 15%.
As punters, we will face the same challenges as usual on these types of stages in recent years - the General Classification contenders should have the stage honours between them, but that will much depend on their appetite for bringing back the breakaway.
Who are the favourites?
Jai Hindley (5.509/2), Richard Carapaz (6.005/1) and Mikel Landa (12.0011/1) - if the evidence of Stage 16 is anything to go by - are in the most consistent climbing form of any in the Giro and, breakaway risk aside, should have the stage between them.
Landa is probably due his habitual nightmare stage. That day visits him in every Grand Tour and he can't be backed with any confidence.
Which leaves Hindley as the best bet. He consistently has the measure of Carapaz in sprint finishes and will again likely go for the bonus seconds available on the line.
Who are the most likely outsiders?
A host of riders could feature if a breakaway is allowed some rope. At big odds, it might be worth taking a risk on the 22-year-old Colombian, Santiago Buitrago (30.0029/1) at big odds. He looked in good form on Stage 15 and is still looking for his first major stage win in a Grand Tour.
What effect will it have on the overall markets?
Another crucial day. The Giro has most likely boiled down now to a match between Carapaz and Hindley, and neither of them will want to leave it to the time trial on the last day to decide things. Experience says that Carapaz will find a way to wear Hindley down and put in a significant time gap, but Stage 20 looks to be the day for his all-out assault.
*Odds correct at the time of writing