The hot water bottle cover is knit to fit a ~2L hot water bottle measuring 33cm in height x 20cm in width.

The cover is knit in two panels in stockinette stitch and an intarsia argyle pattern, while leaving stitches on-hold at the neck to be joined in the round at the end. The panels are seamed to create a cover fitting the bottle, and the on-hold stitches at the neck are joined to be worked in the round to create a neck for the funnel of the bottle.

Hot Water Bottle Cover (on 4mm)

Measurements: 21cm x 34cm
Gauge: 17 sts x 22 rows = 10 x 10 cm 4 x 4 inches in stockinette on 4mm
Needles: 4mm - circular or straight needles can be used to knit the body of the cover, but the neck is knitted on circular needles in magic loop or double pointed needles
Materials: Approx. 68 g ~DK weight yarn in at least 4 colours, so ~18g per colour for 4 colours, ~12g per colour for 6 colours

Hot Water Bottle Cover (on 5mm)

Measurements: 21cm x 34cm
Gauge: 13 - 14 sts x 19 rows = 10 x 10 cm 4 x 4 inches in stockinette on 5mm
Needles: 5mm - circular or straight needles can be used to knit the body of the cover, but the neck is knitted on circular needles in magic loop or double pointed needles
Materials: Approx. 90 g ~aran weight yarn in at least 4 colours, so ~23g per colour for 4 colours, ~15g per colour for 6 colours

Techniques used in this pattern:
stockinette,
joining in the round,
mattress stitch,
intarsia,
duplicate stitch