Fisher Space Pen 3 Pack Black SPR4 Refills for Bullet

If this is your question:-You: 'Will this refill fit in my Space Pen?'I'll save you some time:-Me: 'Yes, yes it will'The SPR4 fits in ANY Space Pen with the exception of one: The Q4; The Q4 is the multi-ink Space Pen that has red ink, black ink and a pencil. So if your space pen writes in only one colour and hasn't been hiding a pencil lead for the time you've been using it, this is the refill for you (assuming you want black ink, in a medium gauge).I'm not a Space Pen geek, the following is the sum of experience of using the product daily and about 5 minutes of research.These are genuine Space Pen pressurised refills with black ink. They have a medium-sized ball in the tip - this ball is 1.1mm in circumference (and made of tungsten carbide).The first of these refills actually writes slightly better than the one that came with my Space Pen, giving a more comfortable 'glide' over paper and plastic. It writes well on a range of surfaces and at any orientation, allowing you to use a vertical wall to lean on if you need to.Not being an astronaut, I can't tell you if it writes in space :(Some basic information about Space Pen refills that you may find useful:SPR1 - Blue MediumSPR1F - Blue Fine (0.9mm)SPR1B - Blue Bold (1.3mm)SPR2 - Red mediumSPR2F - Red fineSPR3 - Green MediumSPR3F - Green FineSPR4 - Black MediumSPR4F - Black FineSPR4B - Black Boldrefills available in one size*: SPR5 - Burgundy, SPR6 - Purple, SPR8 - Brown, SPR9 - Turquoise, SPRSL - Silver(*I don't know why there isn't an SPR7.)

I used to use a Cross pen but found it hard to get refills. This is a great replacement if you want to use something more reliable and better quality than a regular plastic disposable pen. Also there are no leaks.

If you like this ink or need it in your pen this is three of them. For anyone who has not used the ink this is harder to get out of the pen than "normal" ink, but it is a quality product and not having to care what angle you write in is comfortable for me.

Not as easy to write with as previous purchases. Writes at all angles, but needs to be fairly square to the paper to write smoothly. Not had that problem before with Fisher refills/.

The space pen was a marvellous invention . I use it upside down, on damp/grasy paper - great to get refills

These do exactly as they claim. They will allow you to write on walls with the pen pointing ‘uphill’After demonstrating this to my wife my next review will be on some wall cleaner and emulsion paint

Bought these blindly since the product photos, product description or little else on the listing gave me the impression they were the right ones for my space pen. I was lucky.In case it helps (and assuming this review will still be attached to this particular product and a "similar" one by the time you read this), it fits the 400-series "Bullet" pens perfectly. The "Fisher Pressurized PR4, Black Ink, Medium Point" arrived in my case.

Arrived on time and well packaged.Super writer