The most protective water-based finish Mr. Hobby make. Three things are working here at once, and they compound: the Premium formulation lays down a stronger film that resists scratching far better than conventional water-based coats; the UV-cut component filters the light that fades colour and yellows white plastic over years of display; and the smooth clear additive reduces friction on the painted surface itself, so contact points and handling marks stop being inevitable.

Put together, that's the coat for the models you actually care about — the finished display piece, the action-posed kit that gets picked up and re-posed, the shelf by the window. And it does all of it while staying water-based: safe over waterslide decals, safe on clear parts, safe over your paintwork, with none of the crazing or paint-lifting risk that comes with a solvent UV-cut lacquer. If you've avoided UV protection because the lacquer version was too aggressive for your build, this is the answer. At 170ml it's also nearly double the other Premium Top Coat cans.

• Stronger, scratch-resistant Premium film
• UV filtering slows fading and yellowing on display
• Smooth Clear reduces friction and handling marks
• Matt finish — flat and realistic, without a chalky feel
• Water-based: safe over decals, clear parts and painted surfaces
• 170ml — nearly twice the standard Premium Top Coat cans

How to use it: Shake it properly and warm the can in hand-hot water first; water-based clears spit when cold. Let the paint underneath cure fully, then build thin coats rather than one heavy pass. Matt finishes are the most sensitive to humidity of any coat — water-based is far more forgiving than lacquer here, but a dry day still gives a better result than a sticky one.

Tip: This is the coat for kits that get handled rather than just looked at. The friction-reducing property does its best work exactly where models wear first — joint surfaces, contact points, the edges you pick up. On an action-posed build that gets repositioned regularly, it's the difference between paint that lasts and paint that polishes away at the shoulders.

Which one do I need? B-604 when the model is on display, gets handled, or both — it's the full protection package. Premium Top Coat Flat (B-603) for the same tough film without UV filtering, in the smaller 88ml can. Standard Top Coat Flat (B-503) as the economical option for pieces kept behind glass. If you need lacquer hardness and there are no clear parts, decals or water-based paints in play, Mr. Super Clear UV Cut Flat (B-523) goes harder still.

Specifications

Brand: Mr. Hobby (GSI Creos / Gunze Sangyo)
Item No.: B-604
Type: Water-based premium top coat, UV-cut, aerosol
Finish: Matt
Volume: 170ml
Suitable for: Painted plastic, decals, clear parts, bare plastic
Features: UV filtering, scratch-resistant film, friction-reducing
Use in: Well-ventilated area