Parker-Compatible Gel Ink Refills - Water Tests

In an attempt to find a waterproof gel ink pen, as well as Parker-compatible gel refills that are waterproof. I dug out all my gel ink pens and refills and did a quick test. The refills tested here are universal and are compatible with many pens (in my case, they were for my Retro 51). Update** Sorry. This may have been unclear - the pens tested here are not necessarily Parker-compatible (without some hacking), I just added them in to test and compare general gel ink water resistance.

Left

• Uni-ball Vision RT - Waterproof.
• Zebra Sarasa SE 07 - Zebra gel ink pens are water-based ink so they're not supposed to be waterproof, but these look pretty good - although some color bleeds, the words stay.
• Zebra Sarasa 07 - Waterproof (same as Zebra Sarasa SE 07).
• Zebra Sarasa Clip 07 - Waterproof (same as Zebra Sarasa SE 07).
• Uni-ball Signo 207 Ultra Micro - Waterproof.
• Zebra Surari 07 - Waterproof.
• Uni-ball Signo 207 - Water resistant - some color washes and because it’s so light already, it looks like it’s washing away - but it’s not! 
• Pilot G-2 07 - Pilot says this is waterproof so what we see here is just some ink bleeding. 
• Pentel WOW! Gel - Waterproof, according to Pentel, but the red did bleed a little.
• Pentel HyperG 07 - Waterproof.
• Pentel EnerGel 07 - Water resistant but the ink does start to fade quickly.
• Pentel Oh! Gel 07 - Doesn’t look waterproof. The ink bleeds and writing starts to fade. 
• Uni-ball Signo DX 0.38 - Waterproof.
• Bic 537 0.7 - Not waterproof - writing fades quickly. I don’t know where the ink goes either because the water isn’t that purple!
• Pentel Slicci 0.7 - Not waterproof... at all.
• Pilot Hi-Tec C 0.4 - Looks waterproof in this case, but some color may bleed. 

Right

• Monteverde Ceramic Rollerball Refills - Not waterproof but handles water decently!
• Monteverde Ceramic Rollerball Refills - Not waterproof but handles water decently!
• Monteverde Ceramic Rollerball Refills - Not waterproof but handles water decently!
• Monteverde Ceramic Rollerball Refills - Not waterproof but handles water decently!
• Monteverde Ceramic Rollerball Refills - Not waterproof but handles water decently!
• Monteverde Ballpoint Refills for Parker Pens (soft roll) - Handles water. Not sure if ballpoints qualify as “waterproof”.
• Monteverde Ballpoint Refills for Parker Pens (soft roll) - Handles water. Not sure if ballpoints qualify as “waterproof”.
• Monteverde Ballpoint Refills for Parker Pens (soft roll) - Handles water. Not sure if ballpoints qualify as “waterproof”.
• Monteverde Ballpoint Refills for Parker Pens (soft roll) - Handles water. Not sure if ballpoints qualify as “waterproof”.
• Monteverde Gel Refills for Parker Pens - Not waterproof.
• Monteverde Gel Refills for Parker Pens - Not waterproof. 
• Mont Blanc Rollerball - Not waterproof.
• Mont Blanc Rollerball - Not waterproof.

Based on some research, I have found people recommending a few different refills for Parker-compatible gel refills.

Waterproof gel refill recommendations:

Schneider Pen Gelion 1 Refills
Visconti AA38 - I think these are waterproof...anyone know?

Water resistant gel refill recommendations:
Cross Selectip Gel

Other:

Ballpoint - Schmidt® Refill P900

Gel ink pen recommendations:
Uni-ball Signo 207
Uni-ball Signo DX 0.38
Uni-ball Signo 207 Ultra Micro
Pilot Hi-Tec C

If you're purchasing a refill for a particular pen, I would suggest taking the old refill to the store and double checking the size, or make sure the refill states it fits that particular brand. If you are interested in any of the Monteverde refills from the right page, remember, I got them at Office Depot on an awesome clearance!