Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uni-Ball Signo RT1 Gel Ink Pen 0.5mm Blue Box of 10
Uniball

Uni-ball Signo RT1 UMN155-05 Retractable Gel Ink Rollerball Pen 0.5mm Blue Box of 10

$22.46 inc GST
$22.46 inc GST
RRP $23.87
Or 4 payments of $5.62 with
Add items to a quote for bulk pricing, approvals, or purchase orders.

SKU: UMUMN155-05BL

UPC: 34902778142753

MPN: UMN155-05BL

Blue Gel Ink at a 0.5mm Width

This is the blue version of the uni-ball Signo RT1, a retractable gel ink pen that uni-ball's 2026 catalogue publishes at a 0.5mm line width.

Plenty of organisations still want blue for anything signed, on the reasoning that a blue signature is visibly an original rather than a copy. That convention is why a blue pen and a black pen tend to sit in the same drawer. At 0.5mm the line is fine enough to sit inside a form box and still substantial enough to read across a full page, which is the balance most ordinary paperwork asks for.

uni-ball publishes the RT1 as a retractable pen, so it clicks shut rather than taking a cap. The ink is published as gel ink, with uni-ball's own page calling it new improved gel ink. The group code is UMN-155 and uni-ball's site writes this width as UMN155-05, which is the string to quote when reordering.

The matching black and the other colours are at gel pens, and the finer 0.38mm width of this same model is there too. More uni-ball is at uni-ball, and other writing at writing supplies.

Often ordered together

  • Retractable, as published by uni-ball for the Signo RT1
  • Gel ink, described on uni-ball's own page as new improved gel ink
  • 0.5mm line width, per uni-ball's 2026 product catalogue
  • Blue ink, where a signature needs to read as an original
  • uni-ball publishes the model under the group code UMN-155, this width as UMN155-05
  • Supplied as a box of 10, all one colour
  • Signing contracts, forms and authorisations
  • General office and counter writing
  • Keeping a two-colour desk set with the black version
  • Reception, dispatch and warehouse paperwork
  • Bulk refresh of a stationery cupboard

Shipping

Shipping is kept simple with flat rates for selected areas and free shipping where applicable. Large, bulky, rural or out-of-area orders may require additional freight, and our team will contact you if this applies. For a more specific estimate, simply add this product to a quote or visit our shipping page.

Delivery Times

Melbourne, Sydney, Brisbane, Adelaide — 1 to 3 business days
Perth — 1 to 5 business days
Regional & Outer Areas — 3 to 7 business days

Returns

If you have questions about returns, please contact us or visit our returns page for full details.

Specifications

Brand: uni-ball

Range: Signo RT1

Model Group: UMN-155

Manufacturer Code: UMN155-05

Mega Code: UMUMN155-05BL

Colour: Blue

Line Width: 0.5mm (uni-ball's 2026 product catalogue)

Ink Type: Gel ink

Mechanism: Retractable

Pack: Box of 10

Primary Distribution Centre

Factory 5, 12 Greenway Drive
Tweed Heads South NSW 2486

ABN 18 634 002 609

Get directionsContact us

FAQs

0.5mm. uni-ball's 2026 product catalogue lists the Signo RT1 in three widths, 0.38mm, 0.5mm and 0.7mm, and UMN155-05 is the 0.5mm version.
Retractable. uni-ball's product page describes the Signo RT1 as an ultra fine retractable rollerball pen, so there is no cap.
uni-ball's website writes this width as UMN155-05, while uni-ball's 2026 catalogue uses a different pattern for the family, writing the finer 0.38mm pen as UMN-155-38. The website code UMN155-05 is the one for this 0.5mm pen.
One box of 10 uni-ball Signo RT1 UMN155-05 retractable gel ink rollerball pens, all in blue ink, each with a 0.5mm line.

Shipping & Delivery

Delivery time depends on your location, the size of your order, and the shipping option selected at checkout. For in-stock items, standard metro delivery in QLD, NSW and VIC is usually 1 to 7 business days. South Australia, Tasmania, Western Australia and the Northern Territory are generally 3 to 12 business days. Express delivery for eligible parcels under 3kg is usually 1 to 4 business days in QLD, NSW, ACT and VIC. Delivery estimates apply to in-stock items only and may vary due to carrier conditions or delays.

If you need to make a change to your order, please contact our team as soon as possible. Once an order has been processed or dispatched, changes may no longer be possible. You can contact us through our Contact Us page for assistance.

Mega Office Supplies ships orders Australia wide and occasionally internationally. The best avenue would be to contact us so we can customise a specific quote for you. Please note that associated international duties, taxes and levies will be the responsibility of the customer.

Returns, Refunds & Replacements

Mega Office Supplies accepts change-of-mind returns for unopened and unused products within 14 days from the invoice date, provided the item is returned in its original packaging and in resalable condition. Original shipping costs are not refundable, return shipping is the customer’s responsibility, and a restocking fee may apply depending on the product type and supplier. Some items, including electronics, assembled or installed furniture, food, beverages, medicines, custom-made products, and certain bulk or special-order items, are not eligible for return unless required under Australian Consumer Law.

If your order arrives faulty, damaged, or incorrect, please contact Mega Office Supplies as soon as possible. Where required under Australian Consumer Law, a repair, replacement, or refund will be offered. In these cases, Mega Office Supplies will cover reasonable return shipping costs, and photographic evidence may be requested to help process the claim. Items should be reported within a reasonable timeframe after delivery.