Stupid n00b question

[TylerD]

I'm looking at the English Premiership market for Saturday's game on Pinnacle.

Under the Spread option it's priced as follows:

Sat 11/5 1 Aston Villa * pk and +0.5 1.952
04:43 AM 2 Liverpool * pk and -0.5 1.952

and some are:

Sat 11/5 4 Arsenal -1.5 and -2 2.070
06:58 AM 5 Sunderland +1.5 and +2 1.813

What does this all mean? I get the odds but what does pk mean and why are there two spread options?

TIA