Sanwa Supply will release the casual PC backpack "BAG-BP18BK," weighing 550g with a 17L capacity, in late May 2026[1][2]. The bag is designed to carry a 15.6-inch or 16-inch wide notebook PC together with an 11-inch tablet, and its headline feature is squeezing all of that into roughly the same weight as a 500ml PET bottle[1]. The list price is 8,580 yen (7,800 yen before tax), and the bag ships in a single black colorway with a clean, minimal design that fits both business and casual use[1][2].

A lightweight build seen through the numbers: 550g and 17L

The BAG-BP18BK has a body weight of 550g, almost the same as a 500ml PET bottle (about 500g)[1][2]. The previous casual PC backpack, the 15.6-inch-class "BAG-BP17" series launched in January 2025, weighed 540g[3]. The new model extends compatibility to 16-inch wide notebooks while limiting the added weight to just 10g.

The external dimensions are roughly W310×D120×H440mm, with internal dimensions of W300×D80×H430mm in a single-compartment layout, for a total capacity of 17L[2]. The exterior uses a firm polyester fabric chosen to resist losing its shape[1][2]. The back panel and the inside of the shoulder straps and grab handle are made of mesh to reduce stuffiness, with cushioning that takes pressure off the shoulders and hand[1].

A 17L capacity is enough to comfortably hold a notebook, tablet, change of clothes, and small accessories, and the fact that all of that is packed into a 550g shell makes the engineering intent here easy to read[1][2].

Cushioned 16-inch wide PC sleeve and multi-functional storage

The PC compartment is a cushioned sleeve measuring W280×D30×H400mm internally, supporting notebook PCs up to 15.6 or 16-inch wide[1][2]. A separate cushioned tablet pocket of W200×D10×H240mm is provided for an 11-inch tablet, so a PC and a tablet can each ride in their own padded slot[1][2].

For smaller items, the front pocket measures W265×D20×H240mm and contains two W145×H170mm inner pockets, while the main room has two additional W130×H150mm inner pockets[2]. The side pockets are W80×D10×H170mm on each side, and one of them can stretch in depth to hold a PET bottle[2].

The JAN code is 4969887714683, the bag is a single-compartment design with a carry-strap supporter, and the shoulder strap length is adjustable[1][2]. The carry-strap supporter allows the bag to slip onto a suitcase handle for travel, while the lack of bottom studs makes setting the bag directly on outdoor surfaces less ideal[2].

Priced at 8,580 yen, positioned as the standard option that puts lightness front and center

The list price is 8,580 yen (7,800 yen before tax), which sits in the standard pricing band of Sanwa Supply's casual PC backpack lineup[1][2]. The slightly lighter, 15.6-inch BAG-BP17 series (540g) remains in the lineup[3], so the BAG-BP18BK is being added as the option for users who actually carry a 16-inch notebook.

Sanwa Supply pitches the bag for commuting and school use as well as for "on/off" scenarios like gym stops after work or weekend outings, with a deliberately understated solid black finish[1]. Ultra-light bags often suffer from thin fabric and easy deformation; the choice of a firm polyester here is a thoughtful touch for people who tend to leave the bag standing on a desk or floor all day[1][2].

There are not many 16-inch-class PC backpacks that combine a true 17L capacity with a 550g body weight, which makes the BAG-BP18BK a strong candidate for anyone who treats weight as the top priority.

Summary

Sanwa Supply's "BAG-BP18BK" is a casual PC backpack with a 550g body, 17L capacity, support for 15.6 or 16-inch wide notebooks and an 11-inch tablet, listed at 8,580 yen (7,800 yen before tax)[1][2]. Compared with the 15.6-inch BAG-BP17 series (540g), it extends the size compatibility while limiting the weight increase to just 10g, and rounds out the design with everyday details like a firm polyester fabric, a mesh back panel, and a built-in carry-strap supporter — adding up to a sensibly polished pick for people who carry a notebook every day[1][2][3].

Source [1]: https://www.sanwa.co.jp/info/news/202605/bag-bp18bk/index.html

Source [2]: https://www.sanwa.co.jp/product/syohin?code=BAG-BP18BK

Source [3]: https://pc.watch.impress.co.jp/docs/news/1654269.html