The app is free. The key is the only thing you buy.

• Physicians — Sketch a nerve pathway from memory, then check every branch against your atlas.
• Surgeons — Walk an operation through in your head, step by step, before you look at your notes.
• Dentists — Take a case that took longer than expected and find what the radiograph was telling you.
• Pharmacists — Write the interactions you check most often from memory, then open your formulary.
• Nurses — Rehearse a handover aloud in your unit's format, then compare it with what you wrote.
• Physiotherapists — List the contraindications for a technique you use daily, then check your reference.
• Advocates — Write out a procedural rule from memory, then open the bare act and mark what you missed.
• Chartered accountants — Work one disclosure you always look up, then check it against the standard.
• Company secretaries — Reconstruct a filing deadline calendar from memory and verify it against the rules.
• Bankers — Build a one-page ratio sheet from your institution's own credit policy definitions.
• Architects — Redraw a detail you have drawn a hundred times, then check it against the code.
• Civil engineers — Size a member by hand on paper, then check it against the design you submitted.
• Mechanical engineers — Refine the mesh on a model you solved recently and see whether it had really converged.
• Electrical engineers — Trace a protection scheme from memory, then check the settings against the relay manual.
• Electricians — Calculate conduit offsets from memory, then check them against your pocket guide.
• Mechanics — Take a fault that fooled you and write down the test that would have found it first.
• Software engineers — Sketch the service you own from memory, then mark where the timeouts actually live.
• Data scientists — Write the assumptions behind a model you shipped, then check them against the data.
• Product managers — Take a launch that missed and find the earliest signal that warned you.
• Designers — Redraw a screen you shipped without opening the file, then compare the two.
• School teachers — Plan one lesson's hardest five minutes on paper, then check it against the syllabus.
• Professors — Explain a paper you assign to somebody outside your field, out loud, in plain words.
• Researchers — Write the method of your current study from memory and find the step you skipped.
• Journalists — Read something written for people on your beat, with one question to answer by the end.
• Civil servants — Take a file you decided and write the strongest argument against your own order.
• Founders — Calculate your runway on paper from memory, then check it against your statements.
• Sales professionals — Say your three commonest objections and their answers out loud, under a minute each.
• Marketing managers — Take a campaign that missed and trace where the audience stopped behaving as forecast.
• Shopkeepers — Count what moved this week from memory, then check the till roll.
• School students — Empty a chapter onto blank paper from memory, then fill the gaps in another colour.
• Engineering students — Cover a worked example and solve it yourself, then find the line where you diverged.
• Medical students — Draw a pathway and label it from memory, then check the atlas.
• UPSC aspirants — Write one answer by hand against the clock, then compare its shape with the syllabus.
• CA aspirants — Work one problem end to end without the solution beside you.
• Law students — Reconstruct a judgment's reasoning in five lines, then read it again.
• MBA aspirants — Take a case you have read and argue the side you did not choose.
• Chefs — Write a station's whole mise en place from memory, then check your prep sheet.
• Tailors — Take a garment that fought you and redraw the alteration on paper.
• Photographers — Pick a frame that felt cramped and write down what a different lens would have done.
• Artists — Test three background values on scrap before you commit one to the canvas.
• Musicians — Play a piece through in your head, without the instrument, and find where it slows.
• Dancers — Mark a phrase in silence and notice where your mental map hesitates.
• Cricketers — Watch one over of a batter you admire and note the trigger movement.
• Athletes — Run your event in your head at real speed, then write what your attention did.
• Yoga instructors — Read your own teaching notes for a sequence, then say the cues aloud without them.
• Massage therapists — Recall the contraindications you check for, then compare with your training notes.
• Homemakers — Write the stain treatments you use from memory, then check the care guide.
• Retired — Read one chapter with a pencil, and write the one idea worth keeping.
• Between jobs — Take one thing you did well and write it as three lines somebody else could read.
• Delivery partners — Redraw today's route from memory and mark where the minutes actually went.

• Shipping, anywhere in India our couriers reach.
• A GST invoice, on request.
• Replacement, free and including postage, if it arrives damaged or doesn't work and you tell us within seven days, with a photo.
• A one-year warranty against manufacturing defects.
• The app, its modes, its schedules and every update to them.

Not covered, so that it is said plainly: battery replacement, physical damage, water damage and loss. The Bluetooth Spark takes a CR2032 coin cell you can buy anywhere; the NFC Spark has no battery. Full detail in the refund and cancellation policy.

The rest of them — enforcement limits, lost keys, what happens with Bluetooth off — are on the FAQ.