FD mark
FlatlineDynamics
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SYSTEMS▸KEYSTONE 25 · A03
◀ REGISTRY · 02/DOSSIER · FD-K25
ACTIVE · PUBLIC
PROGRAMME 01 · CARRY · TIER 2 · CLAMSHELL RUCKSACK · EXTERNAL FRAME

KEYSTONE
25 · A03

“Most carry hardware fails not because it was the wrong choice · but because it cannot be maintained on the operator's back.”

Keystone 25 is a 24-litre clamshell-opening rucksack on an external alloy frame · small enough to run as an assault pack, where external frames usually mean bulk. The frame is the point: it makes the pack field-repairable and lets it expand with mission requirements as they change. A removable hip belt and zip-up side pockets sit over modular attachment points, so capacity and role grow as the task demands. Standalone by default · it docks with the rest of the Flatline system when you want it to, never because you have to.

UNIT TELEMETRY
1.18KG
MEASURED ◢ TARGET ≤ 1.20 KG · MARGIN 20 G UNDER
FORMATCLAMSHELL
FRAMEEXT · ALLOY
VOLUME · BASE24 L · EXPANDS
HIP BELTREMOVABLE
SIDE POCKETSZIP · MODULAR
REPAIR CLASSA · FIELD
STRIP TIME9 MIN MEAN
LOAD RATING32 KG · STAMPED
01
LOADOUT CONFIGURATOR · BUILD A PROFILE
◢◤ FD-K25/REV.A03

One chassis. Multiple roles.

All primary fasteners standardised to two sizes. Panel joints use captured hardware — nothing to lose forward. Load points rated and stamped. The chassis accepts harness variants without structural modification.
FASTENERS
2 SIZES ONLY
T20 + T10 · field spares kit
PANEL JOINTS
CAPTURED HARDWARE
nothing to lose or source forward
LOAD POINTS
RATED + STAMPED
not implied — tested and marked
HARNESS IF
NO STRUCT. MOD
accepts V1–V3 without frame change
OPTICHMDHMDSVCBIONETOPTICBIOGEN
PROFILE · RECCE
SENTINEL · POWERED
OPERATOR PROFILE5 PRESETS
RECCE · long-loop · low-signature observation
LIVE READOUT
CARRIED · MASS
5.50KG
VOLUME · USED
7.4/ 24 L
LOAD vs 32 KG STAMPED17%
CENTRE OF GRAVITY · FRAME-RELATIVE
HIGH · TOPCENTREDLOW · HIP
ROSTER · 9 MODULES FITTED6 CLASSES
TOP-AIR ILLUMINATOROPTIC180G
INT-PUSENTINEL · PUHMD240G
INT-BTSENTINEL · BATTHMD360G
INT-SPKSPARES KITSVC200G
L-AHYDRATION 2LBIO2120G
L-BCOMMS POUCHNET920G
R-ATHERMAL OPTICOPTIC460G
R-BIFAK · TIER 1BIO280G
BOTBIVY ROLLGEN740G
BAYS · FILLED
9 / 9
OF AVAILABLE BAYS
PACK · TOTAL
6.68 KG
CARRIER 1.18 + MODULES
HMD · LINKED
YES
PU + BATT IN BAYS
BALANCE · COG
HIGH
WEIGHT BIAS
02
WEIGHT BUDGET
◢◤ FD/REV.A03

Every gram recorded.

Sub-1.2 kg target held through every revision. No feature added without a weight trade.
WEIGHT IS A CONSTRAINT,
NOT AN OUTCOME.
The sub-1.2 kg target was set early and held through every revision. No feature was added without a weight trade recorded in the revision log. Hover any module to see what it costs the budget.
MEASURED
1180G
TARGET CEILING
≤ 1200G
540G
220G
180G
140G
86G
14G
20G
0 G500 G1000 G▲ 1200 G TARGET
CHASSIS
540 G
PRIMARY CHASSIS · 6061-T6
LID
220 G
LID + HARDWARE
HARNESS
180 G
HARNESS · V3 STANDARD
COMP-A
140 G
COMPARTMENT INSERTS · 6x
FASTENERS
86 G
FASTENERS · ALL CAPTURED
STAMP
14 G
LOAD STAMP + LABELS
MARGIN
20 G
BUDGET MARGIN · UNDER
03
REVISION LOG
◢◤ FD/REV.A03

Three revisions. Two years.

Every trade stamped. No feature without a log entry.
▲ CURRENT
A03
CURRENT · FIELD-SERVICEABLE
Two-size fastener doctrine, captured hinge pins, harness V3 versioned interface. 1.18 kg.
2026.04
▸ DELTAS
MASS1.18 KG · −90 G
FASTENERS14 · 2 SIZES
HARNESSV3 · VERSIONED IF
HINGECAPTURED PIN · INF
▸ FINDINGS · WHAT THIS REV LEARNED
›9-minute mean strip-and-rebuild verified at FD-LAB · 30 operators.
›Sub-1.2kg target held. No feature added in this revision.
›Harness V3 interface published as FD-DOC-K25-HRN-V3.
04
SERVICE · INTEGRATION
◢◤ FD/REV.A03

Service and integration.

What it takes to keep this in service. Mint = current. Ember = in scope, not yet certified.
FASTENER DISCIPLINETWO STANDARD SIZES THROUGHOUT
SPARES KITFIELD SPARES KIT DOCUMENTED
PANEL ACCESSFULL CLAMSHELL / PANEL-LEVEL
REPLACEABILITYNO FULL-UNIT REMOVAL REQUIRED
INTERFACE DEFINITIONIDD IN PROGRESS
PLATFORM COMPATMOLLE-COMPATIBLE
HARNESS VARIANTSACCEPTED WITHOUT STRUCT. MOD
LOAD POINTSRATED AND STAMPED
CROSS-PROGRAMMESENTINEL HMD-1 · DRAWS FROM BAY INT-PU / INT-BT →
SPARES KIT

Field-replaceable consumables list and supplier references. No OEM portal required.

OPEN SPEC →
OPEN DOCS

Technical documentation, IDD in progress, and field notes published on the lab.

VIEW LAB →
HARNESS V3

Third harness variant drawings open for co-development and integration.

CONTACT →
KEYSTONE 25 · EVALUATION ACCESS
Prototype access is conversational, not transactional.

Keystone 25 is in active prototype. Evaluation units, co-development agreements, and integration discussions are open. Contact opens a channel · not a contract.

OPEN EVALUATION ▸