This book is Moleskine Watercolour Art Plus.
All Jetstream pens are refillable.
I personally use Jetstream 0.5 ballpoint pen for my own sketching and writing since young and it has been a great instrument. Ink flows consistently, with occasional blobs. But that’s what makes it fun, making interesting lines. Personally, I like thinner and neater lines so I use 0.5. 0.7 has somewhat similar design to the 0.5, only difference is the colour.
The 0.5 has a see-through panel to see the ink level while the 0.7 is too dark to see. The grip is good, comfortable and light. 0.7 is all black which makes it look sleek and professional.
When I tried the 0.7 Jetstream ballpoint pen, I thought I expected better. I will explain the pros first then the cons.
Since the line is thicker, it is good for shading bigger areas and outline can be highlighted well. It also produces very black lines. I noticed that it produces darker lines than the 0.5. All three pens worked well with watercolour.
Unfortunately, the ink flow isn’t that good, stopped flowing often. With much more blobs than the 0.5, it's untidy and can cause smudges on the paper. However, it is not fixative proof so it will smudge and spoil your work if you fixative it. The excess blobs can make sketching unpleasant.
If you prefer thicker and darker lines, use this pen but remember the blobs can be annoying.
There are two types of Jetstream 0.7 pens, blue and black.
Jetstream 0.7 (Blue) has a different design from the Jetstream 0.5 and 0.7 (black). It doesn’t have the see through panel like 0.5 does but the rubber grip covers the whole body. 0.5 and 0.7(black) has a tighter rubber grip. The finial is bigger in 0.7 (blue). Although both are from the same series and nib sizes, they uses different refill. The refills are very simillar.
BLACK: SXR-7 JAPAN 14 03-K104
BLUE: SXR-7 JAPAN 13 09-K104
It is very odd that Jetstream 0.7 (Blue), surprisingly, is better than Jetstream 0.7(black) even though they use the same refill. It produces even darker lines and more smooth with better ink flow.
However, it still produces as many blobs as the black one. I suggest you try out both pens before choosing because the same refill can have different results. I have conducted a drop test on the tips of all three Jetstream pens and all are able to ink flow after that. I think the best out of these three is the 0.5, followed by the 0.7 Jetstream pen (blue).
This Jetstream has many nib sizes (1.0, 0.7 and 0.5). They even have the coloured ink versions.
I have tried the light blue coloured one (0.5). I got it from Tokyu Hands Singapore. The some parts of label is in japanese. Refill is SXR-5 JAPAN 12 09-K202
It still creates as many blobs but I think it has a rather nice colour pigment.
The other colours are red, light green, dark green, orange, pink, purple and dark blue.